@article{AmenNagelHedtetal.2020, author = {Amen, Rahma and Nagel, Rebecca and Hedt, Maximilian and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences}, series = {Evolutionary Ecology}, volume = {34}, journal = {Evolutionary Ecology}, number = {3}, publisher = {Springer Science}, address = {Dordrecht}, issn = {0269-7653}, doi = {10.1007/s10682-020-10043-3}, pages = {427 -- 437}, year = {2020}, abstract = {Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype-environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated.}, language = {en} } @misc{AmenNagelHedtetal.2020, author = {Amen, Rahma and Nagel, Rebecca and Hedt, Maximilian and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {3}, issn = {1866-8372}, doi = {10.25932/publishup-51871}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-518714}, pages = {13}, year = {2020}, abstract = {Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype-environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated.}, language = {en} } @article{ApioKabasaKetmaieretal.2010, author = {Apio, Ann and Kabasa, John David and Ketmaier, Valerio and Schroeder, Christoph and Plath, Martin and Tiedemann, Ralph}, title = {Female philopatry and male dispersal in a cryptic, bush-dwelling antelope : a combined molecular and behavioural approach}, issn = {0952-8369}, doi = {10.1111/j.1469-7998.2009.00654.x}, year = {2010}, abstract = {In most mammals, females are philopatric while males disperse in order to avoid inbreeding. We investigated social structure in a solitary ungulate, the bushbuck Tragelaphus sylvaticus in Queen Elizabeth National Park, Uganda by combining behavioural and molecular data. We correlated spatial and social vicinity of individual females with a relatedness score obtained from mitochondrial DNA analysis. Presumed clan members shared the same haplotype, showed more socio-positive interactions and had a common home range. Males had a higher haplotype diversity than females. All this suggests the presence of a matrilineal structure in the study population. Moreover, we tested natal dispersal distances between male and female yearlings and used control region sequences to confirm that females remain in their natal breeding areas whereas males disperse. In microsatellite analysis, males showed a higher genetic variability than females. The impoverished genetic variability of females at both molecular marker sets is consistent with a philopatric and matrilineal structure, while the higher degree of genetic variability of males is congruent with a higher dispersal rate expected in this sex. Evidence even for male long-distance dispersal is brought about by one male carrying a haplotype of a different subspecies, previously not described to occur in this area.}, language = {en} } @misc{AutenriethErnstDeavilleetal.2018, author = {Autenrieth, Marijke and Ernst, Anja and Deaville, Rob and Demaret, Fabien and Ijsseldijk, Lonneke L. and Siebert, Ursula and Tiedemann, Ralph}, title = {Putative origin and maternal relatedness of male sperm whales (Physeter macrocephalus) recently stranded in the North Sea}, series = {Mammalian biology = Zeitschrift f{\"u}r S{\"a}ugetierkunde}, volume = {88}, journal = {Mammalian biology = Zeitschrift f{\"u}r S{\"a}ugetierkunde}, publisher = {Elsevier}, address = {M{\"u}nchen}, issn = {1616-5047}, doi = {10.1016/j.mambio.2017.09.003}, pages = {156 -- 160}, year = {2018}, abstract = {The globally distributed sperm whale (Physeter macrocephalus) has a partly matrilineal social structure with predominant male dispersal. At the beginning of 2016, a total of 30 male sperm whales stranded in five different countries bordering the southern North Sea. It has been postulated that these individuals were on a migration route from the north to warmer temperate and tropical waters where females live in social groups. By including samples from four countries (n = 27), this event provided a unique chance to genetically investigate the maternal relatedness and the putative origin of these temporally and spatially co-occuring male sperm whales. To utilize existing genetic resources, we sequenced 422 bp of the mitochondrial control region, a molecular marker for which sperm whale data are readily available from the entire distribution range. Based on four single nucleotide polymorphisms (SNPs) within the mitochondrial control region, five matrilines could be distinguished within the stranded specimens, four of which matched published haplotypes previously described in the Atlantic. Among these male sperm whales, multiple matrilineal lineages co-occur. We analyzed the population differentiation and could show that the genetic diversity of these male sperm whales is comparable to the genetic diversity in sperm whales from the entire Atlantic Ocean. We confirm that within this stranding event, males do not comprise maternally related individuals and apparently include assemblages of individuals from different geographic regions. (c) 2017 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.}, language = {en} } @article{AutenriethHartmannLahetal.2018, author = {Autenrieth, Marijke and Hartmann, Stefanie and Lah, Ljerka and Roos, Anna and Dennis, Alice B. and Tiedemann, Ralph}, title = {High-quality whole-genome sequence of an abundant Holarctic odontocete, the harbour porpoise (Phocoena phocoena)}, series = {Molecular ecology resources}, volume = {18}, journal = {Molecular ecology resources}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {1755-098X}, doi = {10.1111/1755-0998.12932}, pages = {1469 -- 1481}, year = {2018}, abstract = {The harbour porpoise (Phocoena phocoena) is a highly mobile cetacean found across the Northern hemisphere. It occurs in coastal waters and inhabits basins that vary broadly in salinity, temperature and food availability. These diverse habitats could drive subtle differentiation among populations, but examination of this would be best conducted with a robust reference genome. Here, we report the first harbour porpoise genome, assembled de novo from an individual originating in the Kattegat Sea (Sweden). The genome is one of the most complete cetacean genomes currently available, with a total size of 2.39 Gb and 50\% of the total length found in just 34 scaffolds. Using 122 of the longest scaffolds, we were able to show high levels of synteny with the genome of the domestic cattle (Bos taurus). Our draft annotation comprises 22,154 predicted genes, which we further annotated through matches to the NCBI nucleotide database, GO categorization and motif prediction. Within the predicted genes, we have confirmed the presence of >20 genes or gene families that have been associated with adaptive evolution in other cetaceans. Overall, this genome assembly and draft annotation represent a crucial addition to the genomic resources currently available for the study of porpoises and Phocoenidae evolution, phylogeny and conservation.}, language = {en} } @article{BleidornHillErseusetal.2009, author = {Bleidorn, Christoph and Hill, Natascha and Ers{\´e}us, Christer and Tiedemann, Ralph}, title = {On the role of character loss in orbiniid phylogeny (Annelida) : molecules vs. morphology}, issn = {1055-7903}, doi = {10.1016/j.ympev.2009.03.022}, year = {2009}, abstract = {Orbiniid phylogeny is matter of debate and incongruence between hypothesis based on molecules and morphology has been repeatedly reported. Moreover, the phylogenetic position of the "oligochaetoid polychaetes" of the taxon Questa varies between morphological and molecular cladistic analyses. Here, we present a nearly complete mitochondrial genome of Questa ersei. The mitochondrial gene order is roughly identical to known orbiniid taxa. Several translocations of tRNAs are unique to Orbiniidae and Questa when compared to other annelid mitochondrial genomes. Additionally, we assembled sequence data of six genes (18S, 16S, cox1, cox3, nad1, nad4) for a representative orbiniid taxon sampling and analysed all data in concatenation using Maximum Likelihood and Bayesian inference. For comparison with morphology we compiled a morphological data matrix for all taxa included in our molecular analyses. Our results strongly support a close relationship of Questa with orbiniids (sequence data, gene order, an 18 bp indel, morphology), and a position nested within orbiniids is recovered in our sequence based analyses. We demonstrate remarkable incongruence of most included morphological characters with the recovered best ML tree and suppose that repeated independent character loss might be an explanation.}, language = {en} } @article{BleidornLanterbecqEeckhautetal.2009, author = {Bleidorn, Christoph and Lanterbecq, Deborah and Eeckhaut, Igor and Tiedemann, Ralph}, title = {A PCR survey of Hox genes in the myzostomid Myzostoma cirriferum}, issn = {0949-944X}, doi = {10.1007/s00427-009-0282-z}, year = {2009}, abstract = {Using degenerate primers, we were able to identify seven Hox genes for the myzostomid Myzostoma cirriferum. The recovered fragments belong to anterior class (Mci_lab, Mci_pb), central class (Mci_Dfd, Mci_Lox5, Mci_Antp, Mci_Lox4), and posterior class (Mci_Post2) paralog groups. Orthology assignment was verified by phylogenetic analyses and presence of diagnostic regions in the homeodomain as well as flanking regions. The presence of Lox5, Lox4, and Post2 supports the inclusion of Myzostomida within Lophotrochozoa. We found signature residues within flanking regions of Lox5, which are also found in annelids, but not in Platyhelminthes. As such the available Hox genes data of myzostomids support an annelid relationship.}, language = {en} } @misc{BleidornPodsiadlowskiZhongetal.2009, author = {Bleidorn, Christoph and Podsiadlowski, Lars and Zhong, Min and Eeckhaut, Igor and Hartmann, Stefanie and Halanych, Kenneth M. and Tiedemann, Ralph}, title = {On the phylogenetic position of Myzostomida : can 77 genes get it wrong?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44893}, year = {2009}, abstract = {Background: Phylogenomic analyses recently became popular to address questions about deep metazoan phylogeny. Ribosomal proteins (RP) dominate many of these analyses or are, in some cases, the only genes included. Despite initial hopes, hylogenomic analyses including tens to hundreds of genes still fail to robustly place many bilaterian taxa. Results: Using the phylogenetic position of myzostomids as an example, we show that phylogenies derived from RP genes and mitochondrial genes produce incongruent results. Whereas the former support a position within a clade of platyzoan taxa, mitochondrial data recovers an annelid affinity, which is strongly supported by the gene order data and is congruent with morphology. Using hypothesis testing, our RP data significantly rejects the annelids affinity, whereas a platyzoan relationship is significantly rejected by the mitochondrial data. Conclusion: We conclude (i) that reliance of a set of markers belonging to a single class of macromolecular complexes might bias the analysis, and (ii) that concatenation of all available data might introduce conflicting signal into phylogenetic analyses. We therefore strongly recommend testing for data incongruence in phylogenomic analyses. Furthermore, judging all available data, we consider the annelid affinity hypothesis more plausible than a possible platyzoan affinity for myzostomids, and suspect long branch attraction is influencing the RP data. However, this hypothesis needs further confirmation by future analyses.}, language = {en} } @article{BonizzoniBourjeaChenetal.2011, author = {Bonizzoni, Mariangela and Bourjea, Jerome and Chen, Bin and Crain, B. J. and Cui, Liwang and Fiorentino, V. and Hartmann, Stefanie and Hendricks, S. and Ketmaier, Valerio and Ma, Xiaoguang and Muths, Delphine and Pavesi, Laura and Pfautsch, Simone and Rieger, M. A. and Santonastaso, T. and Sattabongkot, Jetsumon and Taron, C. H. and Taron, D. J. and Tiedemann, Ralph and Yan, Guiyun and Zheng, Bin and Zhong, Daibin}, title = {Permanent genetic resources added to molecular ecology resources database 1 April 2011-31 May 2011}, series = {Molecular ecology resources}, volume = {11}, journal = {Molecular ecology resources}, number = {5}, publisher = {Wiley-Blackwell}, address = {Malden}, organization = {Mol Ecology Resources Primer Dev}, issn = {1755-098X}, doi = {10.1111/j.1755-0998.2011.03046.x}, pages = {935 -- 936}, year = {2011}, abstract = {This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.}, language = {en} } @misc{CahsanKiemelWestburyetal.2021, author = {Cahsan, Binia De and Kiemel, Katrin and Westbury, Michael V. and Lauritsen, Maike and Autenrieth, Marijke and Gollmann, G{\"u}nter and Schweiger, Silke and Stenberg, Marika and Nystr{\"o}m, Per and Drews, Hauke and Tiedemann, Ralph}, title = {Southern introgression increases adaptive immune gene variability in northern range margin populations of Fire-bellied toad}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {14}, issn = {1866-8372}, doi = {10.25932/publishup-52388}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-523883}, pages = {17}, year = {2021}, abstract = {Northern range margin populations of the European fire-bellied toad (Bombina bombina) have rapidly declined during recent decades. Extensive agricultural land use has fragmented the landscape, leading to habitat disruption and loss, as well as eutrophication of ponds. In Northern Germany (Schleswig-Holstein) and Southern Sweden (Sk{\aa}ne), this population decline resulted in decreased gene flow from surrounding populations, low genetic diversity, and a putative reduction in adaptive potential, leaving populations vulnerable to future environmental and climatic changes. Previous studies using mitochondrial control region and nuclear transcriptome-wide SNP data detected introgressive hybridization in multiple northern B. bombina populations after unreported release of toads from Austria. Here, we determine the impact of this introgression by comparing the body conditions (proxy for fitness) of introgressed and nonintrogressed populations and the genetic consequences in two candidate genes for putative local adaptation (the MHC II gene as part of the adaptive immune system and the stress response gene HSP70 kDa). We detected regional differences in body condition and observed significantly elevated levels of within individual MHC allele counts in introgressed Swedish populations, associated with a tendency toward higher body weight, relative to regional nonintrogressed populations. These differences were not observed among introgressed and nonintrogressed German populations. Genetic diversity in both MHC and HSP was generally lower in northern than Austrian populations. Our study sheds light on the potential benefits of translocations of more distantly related conspecifics as a means to increase adaptive genetic variability and fitness of genetically depauperate range margin populations without distortion of local adaptation.}, language = {en} } @article{CahsanKiemelWestburyetal.2021, author = {Cahsan, Binia De and Kiemel, Katrin and Westbury, Michael V. and Lauritsen, Maike and Autenrieth, Marijke and Gollmann, G{\"u}nter and Schweiger, Silke and Stenberg, Marika and Nystr{\"o}m, Per and Drews, Hauke and Tiedemann, Ralph}, title = {Southern introgression increases adaptive immune gene variability in northern range margin populations of Fire-bellied toad}, series = {Ecology and Evolution}, volume = {11}, journal = {Ecology and Evolution}, number = {14}, publisher = {John Wiley \& Sons, Inc.}, address = {New Jersey}, issn = {2045-7758}, pages = {15}, year = {2021}, abstract = {Northern range margin populations of the European fire-bellied toad (Bombina bombina) have rapidly declined during recent decades. Extensive agricultural land use has fragmented the landscape, leading to habitat disruption and loss, as well as eutrophication of ponds. In Northern Germany (Schleswig-Holstein) and Southern Sweden (Sk{\aa}ne), this population decline resulted in decreased gene flow from surrounding populations, low genetic diversity, and a putative reduction in adaptive potential, leaving populations vulnerable to future environmental and climatic changes. Previous studies using mitochondrial control region and nuclear transcriptome-wide SNP data detected introgressive hybridization in multiple northern B. bombina populations after unreported release of toads from Austria. Here, we determine the impact of this introgression by comparing the body conditions (proxy for fitness) of introgressed and nonintrogressed populations and the genetic consequences in two candidate genes for putative local adaptation (the MHC II gene as part of the adaptive immune system and the stress response gene HSP70 kDa). We detected regional differences in body condition and observed significantly elevated levels of within individual MHC allele counts in introgressed Swedish populations, associated with a tendency toward higher body weight, relative to regional nonintrogressed populations. These differences were not observed among introgressed and nonintrogressed German populations. Genetic diversity in both MHC and HSP was generally lower in northern than Austrian populations. Our study sheds light on the potential benefits of translocations of more distantly related conspecifics as a means to increase adaptive genetic variability and fitness of genetically depauperate range margin populations without distortion of local adaptation.}, language = {en} } @article{CahsanWestburyParaskevopoulouetal.2021, author = {Cahsan, Binia De and Westbury, Michael V. and Paraskevopoulou, Sofia and Drews, Hauke and Ott, Moritz and Gollmann, G{\"u}nter and Tiedemann, Ralph}, title = {Genomic consequences of human-mediated translocations in margin populations of an endangered amphibian}, series = {Evolutionary Applications}, volume = {14}, journal = {Evolutionary Applications}, number = {6}, publisher = {John Wiley \& Sons, Inc.}, address = {New Jersey}, issn = {1752-4563}, pages = {12}, year = {2021}, abstract = {Due to their isolated and often fragmented nature, range margin populations are especially vulnerable to rapid environmental change. To maintain genetic diversity and adaptive potential, gene flow from disjunct populations might therefore be crucial to their survival. Translocations are often proposed as a mitigation strategy to increase genetic diversity in threatened populations. However, this also includes the risk of losing locally adapted alleles through genetic swamping. Human-mediated translocations of southern lineage specimens into northern German populations of the endangered European fire-bellied toad (Bombina bombina) provide an unexpected experimental set-up to test the genetic consequences of an intraspecific introgression from central population individuals into populations at the species range margin. Here, we utilize complete mitochondrial genomes and transcriptome nuclear data to reveal the full genetic extent of this translocation and the consequences it may have for these populations. We uncover signs of introgression in four out of the five northern populations investigated, including a number of introgressed alleles ubiquitous in all recipient populations, suggesting a possible adaptive advantage. Introgressed alleles dominate at the MTCH2 locus, associated with obesity/fat tissue in humans, and the DSP locus, essential for the proper development of epidermal skin in amphibians. Furthermore, we found loci where local alleles were retained in the introgressed populations, suggesting their relevance for local adaptation. Finally, comparisons of genetic diversity between introgressed and nonintrogressed northern German populations revealed an increase in genetic diversity in all German individuals belonging to introgressed populations, supporting the idea of a beneficial transfer of genetic variation from Austria into North Germany.}, language = {en} } @misc{CahsanWestburyParaskevopoulouetal.2021, author = {Cahsan, Binia De and Westbury, Michael V. and Paraskevopoulou, Sofia and Drews, Hauke and Ott, Moritz and Gollmann, G{\"u}nter and Tiedemann, Ralph}, title = {Genomic consequences of human-mediated translocations in margin populations of an endangered amphibian}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {6}, issn = {1866-8372}, doi = {10.25932/publishup-52314}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-523140}, pages = {14}, year = {2021}, abstract = {Due to their isolated and often fragmented nature, range margin populations are especially vulnerable to rapid environmental change. To maintain genetic diversity and adaptive potential, gene flow from disjunct populations might therefore be crucial to their survival. Translocations are often proposed as a mitigation strategy to increase genetic diversity in threatened populations. However, this also includes the risk of losing locally adapted alleles through genetic swamping. Human-mediated translocations of southern lineage specimens into northern German populations of the endangered European fire-bellied toad (Bombina bombina) provide an unexpected experimental set-up to test the genetic consequences of an intraspecific introgression from central population individuals into populations at the species range margin. Here, we utilize complete mitochondrial genomes and transcriptome nuclear data to reveal the full genetic extent of this translocation and the consequences it may have for these populations. We uncover signs of introgression in four out of the five northern populations investigated, including a number of introgressed alleles ubiquitous in all recipient populations, suggesting a possible adaptive advantage. Introgressed alleles dominate at the MTCH2 locus, associated with obesity/fat tissue in humans, and the DSP locus, essential for the proper development of epidermal skin in amphibians. Furthermore, we found loci where local alleles were retained in the introgressed populations, suggesting their relevance for local adaptation. Finally, comparisons of genetic diversity between introgressed and nonintrogressed northern German populations revealed an increase in genetic diversity in all German individuals belonging to introgressed populations, supporting the idea of a beneficial transfer of genetic variation from Austria into North Germany.}, language = {en} } @article{CanitzKirschbaumTiedemann2020, author = {Canitz, Julia and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Transcriptome-wide single nucleotide polymorphisms related to electric organ discharge differentiation among African weakly electric fish species}, series = {PLoS one}, volume = {15}, journal = {PLoS one}, number = {10}, publisher = {PLoS}, address = {San Francisco, California, US}, issn = {1932-6203}, doi = {10.1371/journal.pone.0240812}, pages = {21}, year = {2020}, abstract = {African weakly electric fish of the mormyrid genus Campylomormyrus generate pulse-type electric organ discharges (EODs) for orientation and communication. Their pulse durations are species-specific and elongated EODs are a derived trait. So far, differential gene expression among tissue-specific transcriptomes across species with different pulses and point mutations in single ion channel genes indicate a relation of pulse duration and electrocyte geometry/excitability. However, a comprehensive assessment of expressed Single Nucleotide Polymorphisms (SNPs) throughout the entire transcriptome of African weakly electric fish, with the potential to identify further genes influencing EOD duration, is still lacking. This is of particular value, as discharge duration is likely based on multiple cellular mechanisms and various genes. Here we provide the first transcriptome-wide SNP analysis of African weakly electric fish species (genus Campylomormyrus) differing by EOD duration to identify candidate genes and cellular mechanisms potentially involved in the determination of an elongated discharge of C. tshokwe. Non-synonymous substitutions specific to C. tshokwe were found in 27 candidate genes with inferred positive selection among Campylomormyrus species. These candidate genes had mainly functions linked to transcriptional regulation, cell proliferation and cell differentiation. Further, by comparing gene annotations between C. compressirostris (ancestral short EOD) and C. tshokwe (derived elongated EOD), we identified 27 GO terms and 2 KEGG pathway categories for which C. tshokwe significantly more frequently exhibited a species-specific expressed substitution than C. compressirostris. The results indicate that transcriptional regulation as well cell proliferation and differentiation take part in the determination of elongated pulse durations in C. tshokwe. Those cellular processes are pivotal for tissue morphogenesis and might determine the shape of electric organs supporting the observed correlation between electrocyte geometry/tissue structure and discharge duration. The inferred expressed SNPs and their functional implications are a valuable resource for future investigations on EOD durations.}, language = {en} } @article{ColangeliSchlaegelOberteggeretal.2019, author = {Colangeli, Pierluigi and Schl{\"a}gel, Ulrike E. and Obertegger, Ulrike and Petermann, Jana S. and Tiedemann, Ralph and Weithoff, Guntram}, title = {Negative phototactic response to UVR in three cosmopolitan rotifers: a video analysis approach}, series = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, volume = {844}, journal = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0018-8158}, doi = {10.1007/s10750-018-3801-y}, pages = {43 -- 54}, year = {2019}, language = {en} } @article{DeCahsanNagelSchedinaetal.2020, author = {De Cahsan, Binia and Nagel, Rebecca and Schedina, Ina-Maria and King, James J. and Bianco, Pier G. and Tiedemann, Ralph and Ketmaier, Valerio}, title = {Phylogeography of the European brook lamprey (Lampetra planeri) and the European river lamprey (Lampetra fluviatilis) species pair based on mitochondrial data}, series = {Journal of fish biology}, volume = {96}, journal = {Journal of fish biology}, number = {4}, publisher = {Wiley-Blackwell}, address = {Oxford [u.a.]}, issn = {0022-1112}, doi = {10.1111/jfb.14279}, pages = {905 -- 912}, year = {2020}, abstract = {The European river lamprey Lampetra fluviatilis and the European brook lamprey Lampetra planeri (Block 1784) are classified as a paired species, characterized by notably different life histories but morphological similarities. Previous work has further shown limited genetic differentiation between these two species at the mitochondrial DNA level. Here, we expand on this previous work, which focused on lamprey species from the Iberian Peninsula in the south and mainland Europe in the north, by sequencing three mitochondrial marker regions of Lampetra individuals from five river systems in Ireland and five in southern Italy. Our results corroborate the previously identified pattern of genetic diversity for the species pair. We also show significant genetic differentiation between Irish and mainland European lamprey populations, suggesting another ichthyogeographic district distinct from those previously defined. Finally, our results stress the importance of southern Italian L. planeri populations, which maintain several private alleles and notable genetic diversity.}, language = {en} } @article{DeCahsanWestburyDrewsetal.2019, author = {De Cahsan, Binia and Westbury, Michael V. and Drews, Hauke and Tiedemann, Ralph}, title = {The complete mitochondrial genome of a European fire-bellied toad (Bombina bombina) from Germany}, series = {Mitochondrial DNA Part B}, volume = {4}, journal = {Mitochondrial DNA Part B}, number = {1}, publisher = {Taylor \& Francis Group}, address = {London}, issn = {2380-2359}, doi = {10.1080/23802359.2018.1547143}, pages = {498 -- 500}, year = {2019}, abstract = {The European fire-bellied toad, Bombina bombina, is a small aquatic toad belonging to the family Bombinatoridae. The species is native to the lowlands of Central and Eastern Europe, where population numbers have been in decline in recent past decades. Here, we present the first complete mitochondrial genome of the endangered European fire-bellied toad from Northern Germany recovered using iterative mapping. Phylogenetic analyses including other representatives of the Bombinatoridae placed our German specimen as sister to a Polish B. bombina sequence with high support. This finding is congruent with the postulated Pleistocene history of the species. Our complete mitochondrial genome represents an important resource for further population analysis of the European fire-bellied toad, especially those found within Germany.}, language = {en} } @misc{DeCahsanWestburyDrewsetal.2019, author = {De Cahsan, Binia and Westbury, Michael V. and Drews, Hauke and Tiedemann, Ralph}, title = {The complete mitochondrial genome of a European fire-bellied toad (Bombina bombina) from Germany}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {532}, issn = {1866-8372}, doi = {10.25932/publishup-42322}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423222}, pages = {3}, year = {2019}, abstract = {The European fire-bellied toad, Bombina bombina, is a small aquatic toad belonging to the family Bombinatoridae. The species is native to the lowlands of Central and Eastern Europe, where population numbers have been in decline in recent past decades. Here, we present the first complete mitochondrial genome of the endangered European fire-bellied toad from Northern Germany recovered using iterative mapping. Phylogenetic analyses including other representatives of the Bombinatoridae placed our German specimen as sister to a Polish B. bombina sequence with high support. This finding is congruent with the postulated Pleistocene history of the species. Our complete mitochondrial genome represents an important resource for further population analysis of the European fire-bellied toad, especially those found within Germany.}, language = {en} } @article{DiGiacomoDiGiacomoKligeretal.2015, author = {Di Giacomo, Adrian S. and Di Giacomo, Alejandro G. and Kliger, Rafi and Reboreda, Juan C. and Tiedemann, Ralph and Mahler, Bettina}, title = {No evidence of genetic variation in microsatellite and mitochondrial DNA markers among remaining populations of the Strange-tailed Tyrant Alectrurus risora, an endangered grassland species}, series = {Bird conservation international}, volume = {25}, journal = {Bird conservation international}, number = {2}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {0959-2709}, doi = {10.1017/S0959270914000203}, pages = {127 -- 138}, year = {2015}, abstract = {The Strange-tailed Tyrant Alectrurus risora (Aves: Tyrannidae) is an endemic species of southern South American grasslands that suffered a 90\% reduction of its original distribution due to habitat transformation. This has led the species to be classified as globally Vulnerable. By the beginning of the last century, populations were partially migratory and moved south during the breeding season. Currently, the main breeding population inhabits the Ibera wetlands in the province of Corrientes, north-east Argentina, where it is resident all year round. There are two remaining small populations in the province of Formosa, north-east Argentina, and in southern Paraguay, which are separated from the main population by the Parana-Paraguay River and its continuous riverine forest habitat. The populations of Corrientes and Formosa are separated by 300 km and the grasslands between populations are non-continuous due to habitat transformation. We used mtDNA sequences and eight microsatellite loci to test if there were evidences of genetic isolation between Argentinean populations. We found no evidence of genetic structure between populations (Phi(ST) = 0.004, P = 0.32; Fst = 0.01, P = 0.06), which can be explained by either retained ancestral polymorphism or by dispersal between populations. We found no evidence for a recent demographic bottleneck in nuclear loci. Our results indicate that these populations could be managed as a single conservation unit on a regional scale. Conservation actions should be focused on preserving the remaining network of areas with natural grasslands to guarantee reproduction, dispersal and prevent further decline of populations.}, language = {en} } @article{DolgenerFreudenbergerSchlucketal.2014, author = {Dolgener, N. and Freudenberger, L. and Schluck, M. and Schneeweiss, N. and Ibisch, P. L. and Tiedemann, Ralph}, title = {Environmental niche factor analysis (ENFA) relates environmental parameters to abundance and genetic diversity in an endangered amphibian, the fire-bellied-toad (Bombina bombina)}, series = {Conservation genetics}, volume = {15}, journal = {Conservation genetics}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {1566-0621}, doi = {10.1007/s10592-013-0517-4}, pages = {11 -- 21}, year = {2014}, abstract = {Increasing attempts are made to understand the factors responsible for both the demographic and genetic depletion in amphibian populations. Landscape genetics aims at a spatially explicit correlation of genetic population parameters to landscape features. Using data from the endangered fire-bellied toad Bombina bombina in Brandenburg (Northeastern Germany), we performed an environmental niche factor analysis (ENFA), relating demographic (abundance) and genetic (diversity at 17 microsatellite loci and partial sequences of the mitochondrial control region in 434 individuals from 16 populations) parameters to ecological and anthropogenic variables such as temperature, precipitation, soil wetness, water runoff, vegetation density, and road/traffic impact. We found significant correlations between road disturbance and observed heterozygosity and between soil wetness and mitochondrial diversity. As the influences of the environmental variables can differ between different indicators for genetic diversity, population size and abundance data, our ENFA-based landscape genetics approach allows us to put various aspects of long- versus short term effective population size and genetic connectivity into an ecological and spatially explicit context, enabling potentially even forecast assessment under future environmental scenarios.}, language = {en} } @article{DolgenerFreudenbergerSchneeweissetal.2014, author = {Dolgener, Nicola and Freudenberger, L. and Schneeweiss, N. and Ibisch, P. L. and Tiedemann, Ralph}, title = {Projecting current and potential future distribution of the Fire-bellied toad Bombina bombina under climate change in north-eastern Germany}, series = {Regional environmental change}, volume = {14}, journal = {Regional environmental change}, number = {3}, publisher = {Springer}, address = {Heidelberg}, issn = {1436-3798}, doi = {10.1007/s10113-013-0468-9}, pages = {1063 -- 1072}, year = {2014}, abstract = {Environmental change is likely to have a strong impact on biodiversity, and many species may shift their distribution in response. In this study, we aimed at projecting the availability of suitable habitat for an endangered amphibian species, the Fire-bellied toad Bombina bombina, in Brandenburg (north-eastern Germany). We modelled a potential habitat distribution map based on (1) a database with 10,581 presence records for Bombina from the years 1990 to 2009, (2) current estimates for ecogeographical variables (EGVs) and (3) the future projection of these EGVs according to the statistical regional model, respectively, the soil and water integrated model, applying the maximum entropy approach (Maxent). By comparing current and potential future distributions, we evaluated the projected change in distribution of suitable habitats and identified the environmental variables most associated with habitat suitability that turned out to be climatic variables related to the hydrological cycle. Under the applied scenario, our results indicate increasing habitat suitability in many areas and an extended range of suitable habitats. However, even if the environmental conditions in Brandenburg may change as predicted, it is questionable whether the Fire-bellied toad will truly benefit, as dispersal abilities of amphibian species are limited and strongly influenced by anthropogenic disturbances, that is, intensive agriculture, habitat destruction and fragmentation. Furthermore, agronomic pressure is likely to increase on productive areas with fertile soils and high water retention capacities, indeed those areas suitable for B. bombina. All these changes may affect temporary pond hydrology as well as the reproductive success and breeding phenology of toads.}, language = {en} } @article{DolgenerSchroederSchneeweissetal.2012, author = {Dolgener, Nicola and Schr{\"o}der, Christiane and Schneeweiss, N. and Tiedemann, Ralph}, title = {Genetic population structure of the Fire-bellied toad Bombina bombina in an area of high population density implications for conservation}, series = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, volume = {689}, journal = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0018-8158}, doi = {10.1007/s10750-012-1016-1}, pages = {111 -- 120}, year = {2012}, abstract = {In this study, we report the genetic population structure of the Fire-bellied toad Bombina bombina in Brandenburg (East Germany) in the context of conservation. We analysed 298 samples originating from 11 populations in Brandenburg using mitochondrial control region sequences and six polymorphic microsatellite loci. For comparison, we included one population each from Poland and Ukraine into our analysis. Within Brandenburg, we detected a moderate variability in the mitochondrial control region (19 different haplotypes) and at microsatellite loci (9-12 alleles per locus). These polymorphisms revealed a clear population structure among toads in Brandenburg, despite a relatively high overall population density and the moderate size of single populations (100-2000 individuals). The overall genetic population structure is consistent with a postglacial colonization from South East-Europe and a subsequent population expansion. Based on genetic connectivity, we infer Management Units (MUs) as targets for conservation. Our genetic survey identified MUs, within which human infrastructure is currently preventing any genetic exchange. We also detect an unintentional translocation from South East to North West Brandenburg, presumably in the course of fish stocking activities. Provided suitable conservation measures are taken, Brandenburg should continue to harbor large populations of this critically endangered species.}, language = {en} } @article{DominguezTiedemannReboredaetal.2017, author = {Dominguez, Marisol and Tiedemann, Ralph and Reboreda, Juan C. and Segura, Luciano and Tittarelli, Fabian and Mahler, Bettina}, title = {Genetic structure reveals management units for the yellow cardinal (Gubernatrix cristata), endangered by habitat loss and illegal trapping}, series = {Conservation genetics}, volume = {18}, journal = {Conservation genetics}, publisher = {Springer}, address = {Dordrecht}, issn = {1566-0621}, doi = {10.1007/s10592-017-0964-4}, pages = {1131 -- 1140}, year = {2017}, language = {en} } @article{EppKruseKathetal.2018, author = {Epp, Laura Saskia and Kruse, Stefan and Kath, Nadja J. and Stoof-Leichsenring, Kathleen Rosemarie and Tiedemann, Ralph and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike}, title = {Temporal and spatial patterns of mitochondrial haplotype and species distributions in Siberian larches inferred from ancient environmental DNA and modeling}, series = {Scientific reports}, volume = {8}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-018-35550-w}, pages = {9}, year = {2018}, abstract = {Changes in species' distributions are classically projected based on their climate envelopes. For Siberian forests, which have a tremendous significance for vegetation-climate feedbacks, this implies future shifts of each of the forest-forming larch (Larix) species to the north-east. However, in addition to abiotic factors, reliable projections must assess the role of historical biogeography and biotic interactions. Here, we use sedimentary ancient DNA and individual-based modelling to investigate the distribution of larch species and mitochondrial haplotypes through space and time across the treeline ecotone on the southern Taymyr peninsula, which at the same time presents a boundary area of two larch species. We find spatial and temporal patterns, which suggest that forest density is the most influential driver determining the precise distribution of species and mitochondrial haplotypes. This suggests a strong influence of competition on the species' range shifts. These findings imply possible climate change outcomes that are directly opposed to projections based purely on climate envelopes. Investigations of such fine-scale processes of biodiversity change through time are possible using paleoenvironmental DNA, which is available much more readily than visible fossils and can provide information at a level of resolution that is not reached in classical palaeoecology.}, language = {en} } @misc{EppKruseKathetal.2018, author = {Epp, Laura Saskia and Kruse, Stefan and Kath, Nadja J. and Stoof-Leichsenring, Kathleen Rosemarie and Tiedemann, Ralph and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike}, title = {Temporal and spatial patterns of mitochondrial haplotype and species distributions in Siberian larches inferred from ancient environmental DNA and modeling}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1052}, issn = {1866-8372}, doi = {10.25932/publishup-46835}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-468352}, pages = {11}, year = {2018}, abstract = {Changes in species' distributions are classically projected based on their climate envelopes. For Siberian forests, which have a tremendous significance for vegetation-climate feedbacks, this implies future shifts of each of the forest-forming larch (Larix) species to the north-east. However, in addition to abiotic factors, reliable projections must assess the role of historical biogeography and biotic interactions. Here, we use sedimentary ancient DNA and individual-based modelling to investigate the distribution of larch species and mitochondrial haplotypes through space and time across the treeline ecotone on the southern Taymyr peninsula, which at the same time presents a boundary area of two larch species. We find spatial and temporal patterns, which suggest that forest density is the most influential driver determining the precise distribution of species and mitochondrial haplotypes. This suggests a strong influence of competition on the species' range shifts. These findings imply possible climate change outcomes that are directly opposed to projections based purely on climate envelopes. Investigations of such fine-scale processes of biodiversity change through time are possible using paleoenvironmental DNA, which is available much more readily than visible fossils and can provide information at a level of resolution that is not reached in classical palaeoecology.}, language = {en} } @article{EppStoofTrauthetal.2010, author = {Epp, Laura Saskia and Stoof, Kathleen R. and Trauth, Martin H. and Tiedemann, Ralph}, title = {Historical genetics on a sediment core from a Kenyan lake : intraspecific genotype turnover in a tropical rotifer is related to past environmental changes}, issn = {0921-2728}, doi = {10.1007/s10933-009-9379-7}, year = {2010}, abstract = {Using molecular genetic methods and an ancient DNA approach, we studied population and species succession of rotifers of the genus Brachionus in the Kenyan alkaline-saline crater lake Sonachi since the beginning of the 19th century as well as distribution of Brachionus haplotypes in recent and historic sediments of other lakes of the East African Rift System. The sediment core record of Lake Sonachi displays haplotypes of a distinct evolutionary lineage in all increments. Populations were dominated by a single mitochondrial haplotype for a period of 150 years, and two putatively intraspecific turnovers in dominance occurred. Both changes are concordant with major environmental perturbations documented by a profound visible change in sediment composition of the core. The first change was very abrupt and occurred after the deposition of volcanic ash at the beginning of the 19th century. The second change coincides with a major lake level lowstand during the 1940s. It was preceded by a period of successively declining lake level, in which two other haplotypes appeared in the lake. One of these putatively belongs to another species documented in historical and recent Kenyan lake sediments. The analysis of plankton population dynamics through historical time can reveal patterns of population persistence and turnover in relation to environmental changes.}, language = {en} } @article{FeulnerKirschbaumSchugardtetal.2006, author = {Feulner, Philine G. D. and Kirschbaum, Frank and Schugardt, Christian and Ketmaier, Valerio and Tiedemann, Ralph}, title = {Electrophysiological and molecular genetic evidence for sympatrically occuring cryptic species in African weakly electric fishes (Teleostei : Mormyridae : Campylomormyrus)}, issn = {1055-7903}, doi = {10.1016/j.ympev.2005.09.008}, year = {2006}, abstract = {For two sympatric species of African weakly electric fish, Campylomormyrus tamandua and Campylomormyrus numenius, we monitored ontogenetic differentiation in electric organ discharge (EOD) and established a molecular phylogeny, based on 2222 bp from cytochrome b, the S7 ribosomal protein gene, and four flanking regions of unlinked microsatellite loci. In C tamandua, there is one common EOD type, regardless of age and sex, whereas in C numenius we were able to identify three different male adult EOD waveform types, which emerged from a single common EOD observed in juveniles. Two of these EOD types formed well supported clades in our phylogenetic analysis. In an independent line of evidence, we were able to affirm the classification into three groups by microsatellite data. The correct assignment and the high pairwise FST values support our hypothesis that these groups are reproductively isolated. We propose that in C numenius there are cryptic species, hidden behind similar and, at least as juveniles, identical morphs.}, language = {en} } @article{FeulnerKirschbaumTiedemann2005, author = {Feulner, Philine g. d. and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Eighteen microsatellite loci for endemic African weakly electric fish (Campylomormyrus, Mormyridae) and their cross species applicability among related taxa}, year = {2005}, abstract = {We describe isolation and characterization of the first microsatellite loci specifically developed for African weakly electric fish (Mormyridae), for the genus Campylomormyrus. Seventeen of our 18 loci are polymorphic within the Campylomormyrus numenius species complex. The polymorphic loci showed four to 15 alleles per locus, an expected heterozygosity between 0.46 and 0.94, and an observed heterozygosity between 0.31 and 1.00. Most primers also yield reproducible results in several other mormyrid species. These loci comprise a set of molecular markers for various applications, from moderately polymorphic loci suitable for population studies to highly polymorphic loci for pedigree analysis in mormyrids}, language = {en} } @article{FeulnerPlathEngelmannetal.2009, author = {Feulner, Philine G. D. and Plath, Martin and Engelmann, Jacob and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Electrifying love : electric fish use species-specific discharge for mate recognition}, issn = {1744-9561}, doi = {10.1098/rsbl.2008.0566}, year = {2009}, abstract = {Mate choice is mediated by a range of sensory cues, and assortative mating based on these cues can drive reproductive isolation among diverging populations. A specific feature of mormyrid fish, the electric organ discharge (EOD), is used for electrolocation and intraspecific communication. We hypothesized that the EOD also facilitates assortative mating and ultimately promotes prezygotic reproductive isolation in African weakly electric fishes. Our behavioural experiments using live males as well as EOD playback demonstrated that female mate recognition is influenced by EOD signals and that females are attracted to EOD characteristics of conspecific males. The dual function of the EOD for both foraging and social communication (including mate recognition leading to assortative mating) underlines the importance of electric signal differentiation for the divergence of African weakly electric fishes. Thus, the EOD provides an intriguing mechanism promoting trophic divergence and reproductive isolation between two closely related Campylomormyrus species occurring in sympatry in the lower Congo rapids.}, language = {en} } @article{FiorentinoManganelliGiustietal.2013, author = {Fiorentino, V. and Manganelli, Giuseppe and Giusti, Folco and Tiedemann, Ralph and Ketmaier, Valerino}, title = {A question of time the land snail Murella muralis (Gastropoda: Pulmonata) reveals constraints on past ecological speciation}, series = {Molecular ecology}, volume = {22}, journal = {Molecular ecology}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.12107}, pages = {170 -- 186}, year = {2013}, abstract = {The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial-temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces. To investigate these questions, we quantified variation on a fine geographical scale analysing morphological (shell) and genetic data sets coupled with environmental data in the land snail Murella muralis, endemic to the Mediterranean island of Sicily. Analysis of a fragment of the mitochondrial DNA cytochrome oxidase I gene (COI) and eight nuclear microsatellite loci showed that genetic variation is highly structured at a very fine spatial scale by local palaeogeographical events and historical population dynamics. Molecular clock estimates, calibrated here specifically for Tyrrhenian land snails, provided a framework of palaeogeographical events responsible for the observed geographical variations and migration routes. Finally, we showed for the first time well-documented lines of evidence of selection in the past, which explains divergence of land snail shell shapes. We suggest that time and palaeogeographical history acted as constraints in the progress along the ecological speciation continuum. Our study shows that testing for correlation among palaeogeography, morphology and genetic data on a fine geographical scale provides information fundamental for a detailed understanding of ecological speciation processes.}, language = {en} } @article{FoersterAsratRamseyetal.2022, author = {Foerster, Verena and Asrat, Asfawossen and Ramsey, Christopher Bronk and Brown, Erik T. and Chapot, Melissa S. and Deino, Alan and D{\"u}sing, Walter and Grove, Matthew and Hahn, Annette and Junginger, Annett and Kaboth-Bahr, Stefanie and Lane, Christine S. and Opitz, Stephan and Noren, Anders and Roberts, Helen M. and Stockhecke, Mona and Tiedemann, Ralph and Vidal, Celine M. and Vogelsang, Ralf and Cohen, Andrew S. and Lamb, Henry F. and Schaebitz, Frank and Trauth, Martin H.}, title = {Pleistocene climate variability in eastern Africa influenced hominin evolution}, series = {Nature geoscience}, volume = {15}, journal = {Nature geoscience}, number = {10}, publisher = {Nature Publ. Group}, address = {London}, issn = {1752-0894}, doi = {10.1038/s41561-022-01032-y}, pages = {805 -- 811}, year = {2022}, abstract = {Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from similar to 620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (similar to 275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (similar to 60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens.}, language = {en} } @article{GessnerArndtTiedemannetal.2006, author = {Gessner, J{\"o}rn and Arndt, Gerd-Michael and Tiedemann, Ralph and Bartel, Ryszard and Kirschbaum, Frank}, title = {Remediation measures for the Baltic sturgeon: status review and perspectives}, series = {Journal of applied ichthyology}, volume = {22}, journal = {Journal of applied ichthyology}, number = {S1}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {0175-8659}, doi = {10.1111/j.1439-0426.2007.00925.x}, pages = {23 -- 31}, year = {2006}, abstract = {More than one century ago, sturgeons were prevalent species in the fish communities of all major German rivers both in the North and the Baltic seas drainages. Since then, the populations declined rapidly due to river damming, overfishing and pollution. The last sturgeon catches in the Baltic drainage system occurred during the late 1960ies. Only a few individual captures have been reported during the last 30 years with the most recent records in the Lake Ladoga ( Russia), where the last confirmed catch was recorded in 1984, and a single individual caught off Estonia in 1996. Today, sturgeons are considered missing or extinct in German waters. First attempts for remediation of the species were undertaken in the mid 1990ies. Subsequently, phylogenetic and population genetic analyses of the species were carried out using mtDNA, microsatellites, and nuclear markers ( SNPs). These genetic analyses using recent and historic material have proven the existence of two different species in the Baltic Sea in what was previously considered to represent the European Atlantic sturgeon only. In the Baltic Sea, the American Atlantic sturgeon ( A. oxyrinchus) succeeded to colonize this brackish water system during the Middle Ages. In the North Sea, the European Atlantic sturgeon ( A. sturio) is considered to be the endemic species. These results led to the separation of the remediation activities in the North Sea and the Baltic Sea tributaries. Further studies on the mechanism that lead to the extinction of A. sturio in Germany and the subsequent succession of the A. oxyrinchus mtDNA haplotype are currently been carried out. Broodstock development using the northernmost populations of A. oxyrinchus is currently under way. As a further prerequisite to re-introduce this species into the Baltic, the evaluation of the status of critical habitats for the early life stages of the American Atlantic sturgeon in the River Odra has been performed in collaboration with the Institute for Inland Fisheries of Poland. Alternative fisheries techniques, based on the data of by-catch of exotic sturgeons in the fishery, are presently developed in close cooperation with the fishery to reduce fisheries related mortality in juvenile sturgeons upon release. Monitoring of habitat utilization and migration characteristics of juvenile fish upon experimental release will have to be carried out shortly, using acoustic telemetry, with the aim to follow the fate of the released fish and to determine the best time-size-release-window for future release programmes.}, language = {en} } @article{GirndtRieschSchroederetal.2012, author = {Girndt, Antje and Riesch, R{\"u}diger and Schr{\"o}der, Christiane and Sehlupp, Ingo and Plath, Martin and Tiedemann, Ralph}, title = {Multiple paternity in different populations of the sailfin molly, Poecilia latipinna}, series = {Animal biology}, volume = {62}, journal = {Animal biology}, number = {3}, publisher = {Brill}, address = {Leiden}, issn = {1570-7555}, doi = {10.1163/157075611X618192}, pages = {245 -- 262}, year = {2012}, abstract = {Rates of multiple paternities were investigated in the sailfin molly (Poecilia latipinna), using eight microsatellite loci. Genotyping was performed for offspring and mothers in 40 broods from four allopatric populations from the south-eastern U.S.A. along a geographic stretch of 1200 km in west-east direction and approximately 200 km from north to south. No significant differences regarding rates of multiple paternities were found between populations despite sample populations stemming from ecologically divergent habitats. Even the most conservative statistical approach revealed a minimum of 70\% of the broods being sired by at least two males, with an average of 1.80-2.95 putative fathers per brood. Within broods, one male typically sired far more offspring than would be expected under an assumed equal probability of all detected males siring offspring.}, language = {en} } @article{GroblerHartlGrobleretal.2005, author = {Grobler, J. P. and Hartl, G. B. and Grobler, N. and Kotze, A. and Botha, K. and Tiedemann, Ralph}, title = {The genetic status of an isolated black wildebeest (Connochaetes gnou) population from the Abe Bailey Nature Reserve, South Africa : Microsatellite data on a putative past hybridization with blue wildebeest (C-taurinus)}, issn = {1616-5047}, year = {2005}, abstract = {The present study aimed at assessing genetic purity of black wildebeest (Connochoetes gnou) at Abe Bailey Nature Reserve, Gauteng Province, South Africa, using a multitocus microsatellite approach. Five loci were studied in black and blue (C. taurinus) wildebeest, the latter being a closely related species and known to produce hybrids with the morphologically very similar black wildebeest. In fact, the entire national black wildebeest population of South Africa potentially contains a significant proportion of introgressed blue wildebeest genes. In our case, eight out of 39 alleles were unique to black and 22 to blue wildebeest, with nine alleles shared between pure populations of the two species in Line with their taxonomic proximity. A possible Limited past introgression of blue wildebeest genes into the Abe Bailey population, corresponding to documents on population history, was only supported by the presence of a single allele otherwise exclusively found in samples of four pure blue but not in samples of two pure black wildebeest control populations. However, an assignment test and coefficients of population divergence did not support an extended introgression of C. taurinus alleles into the C. gnou population under study. Average heterozygosity at Abe Bailey proved to be intermediate between black and blue wildebeest, the tatter species generally harbouring more genetic variation than the former owing to larger population sizes and the absence of population bottlenecks in historical times. The implications of our data are discussed with reference to the persistence of introgressed genes and the conservation of pure black wildebeest gene pools}, language = {en} } @article{GrossClausWohlseinetal.2020, author = {Gross, Stephanie and Claus, Philip and Wohlsein, Peter and Kesselring, Tina and Lakemeyer, Jan and Reckendorf, Anja and Roller, Marco and Tiedemann, Ralph and Siebert, Ursula}, title = {Indication of lethal interactions between a solitary bottlenose dolphin (Tursiops truncatus) and harbor porpoises (Phocoena phocoena) in the German Baltic Sea}, series = {BMC zoology}, volume = {5}, journal = {BMC zoology}, number = {1}, publisher = {BMC}, address = {London}, issn = {2056-3132}, doi = {10.1186/s40850-020-00061-7}, pages = {9}, year = {2020}, abstract = {Background Aggressive interactions between bottlenose dolphins (Tursiops truncatus) and harbor porpoises (Phocoena phocoena) have been reported in different parts of the world since the late 1990s. In the Baltic Sea, harbor porpoises are the only native cetacean species, while bottlenose dolphins may appear there temporarily. In the fall of 2016, a solitary male photo-identified bottlenose dolphin stayed in the German Baltic Sea of Schleswig-Holstein for 3 months. During that time, the necropsies of the stranded harbor porpoises revealed types of trauma of varying degrees in six animals, which is unusual in this area. The purpose of this study was to determine if the appearance of the bottlenose dolphin could be linked to the trauma of the harbor porpoise carcasses. Results Pathological findings in these animals included subcutaneous, thoracic and abdominal hemorrhages, multiple, mainly bilateral, rib fractures, and one instance of lung laceration. These findings correspond with the previously reported dolphin-caused injuries in other regions. Moreover, public sighting reports showed a spatial and temporal correlation between the appearance of the dolphin and the stranding of fatally injured harbor porpoises. Conclusion Despite the fact that no attack has been witnessed in German waters to date, our findings indicate the first record of lethal interactions between a bottlenose dolphin and harbor porpoises in the German Baltic Sea. Furthermore, to our knowledge, this is the first report of porpoise aggression by a socially isolated bottlenose dolphin.}, language = {en} } @article{HartmannHelmNickeletal.2012, author = {Hartmann, Stefanie and Helm, Conrad and Nickel, Birgit and Meyer, Matthias and Struck, Torsten H. and Tiedemann, Ralph and Selbig, Joachim and Bleidorn, Christoph}, title = {Exploiting gene families for phylogenomic analysis of myzostomid transcriptome data}, series = {PLoS one}, volume = {7}, journal = {PLoS one}, number = {1}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0029843}, pages = {8}, year = {2012}, abstract = {Background: In trying to understand the evolutionary relationships of organisms, the current flood of sequence data offers great opportunities, but also reveals new challenges with regard to data quality, the selection of data for subsequent analysis, and the automation of steps that were once done manually for single-gene analyses. Even though genome or transcriptome data is available for representatives of most bilaterian phyla, some enigmatic taxa still have an uncertain position in the animal tree of life. This is especially true for myzostomids, a group of symbiotic ( or parasitic) protostomes that are either placed with annelids or flatworms. Methodology: Based on similarity criteria, Illumina-based transcriptome sequences of one myzostomid were compared to protein sequences of one additional myzostomid and 29 reference metazoa and clustered into gene families. These families were then used to investigate the phylogenetic position of Myzostomida using different approaches: Alignments of 989 sequence families were concatenated, and the resulting superalignment was analyzed under a Maximum Likelihood criterion. We also used all 1,878 gene trees with at least one myzostomid sequence for a supertree approach: the individual gene trees were computed and then reconciled into a species tree using gene tree parsimony. Conclusions: Superalignments require strictly orthologous genes, and both the gene selection and the widely varying amount of data available for different taxa in our dataset may cause anomalous placements and low bootstrap support. In contrast, gene tree parsimony is designed to accommodate multilocus gene families and therefore allows a much more comprehensive data set to be analyzed. Results of this supertree approach showed a well-resolved phylogeny, in which myzostomids were part of the annelid radiation, and major bilaterian taxa were found to be monophyletic.}, language = {en} } @article{HillLeowBleidornetal.2013, author = {Hill, Natascha and Leow, Alexander and Bleidorn, Christoph and Groth, Detlef and Tiedemann, Ralph and Selbig, Joachim and Hartmann, Stefanie}, title = {Analysis of phylogenetic signal in protostomial intron patterns using Mutual Information}, series = {Theory in biosciences}, volume = {132}, journal = {Theory in biosciences}, number = {2}, publisher = {Springer}, address = {New York}, issn = {1431-7613}, doi = {10.1007/s12064-012-0173-0}, pages = {93 -- 104}, year = {2013}, abstract = {Many deep evolutionary divergences still remain unresolved, such as those among major taxa of the Lophotrochozoa. As alternative phylogenetic markers, the intron-exon structure of eukaryotic genomes and the patterns of absence and presence of spliceosomal introns appear to be promising. However, given the potential homoplasy of intron presence, the phylogenetic analysis of this data using standard evolutionary approaches has remained a challenge. Here, we used Mutual Information (MI) to estimate the phylogeny of Protostomia using gene structure data, and we compared these results with those obtained with Dollo Parsimony. Using full genome sequences from nine Metazoa, we identified 447 groups of orthologous sequences with 21,732 introns in 4,870 unique intron positions. We determined the shared absence and presence of introns in the corresponding sequence alignments and have made this data available in "IntronBase", a web-accessible and downloadable SQLite database. Our results obtained using Dollo Parsimony are obviously misled through systematic errors that arise from multiple intron loss events, but extensive filtering of data improved the quality of the estimated phylogenies. Mutual Information, in contrast, performs better with larger datasets, but at the same time it requires a complete data set, which is difficult to obtain for orthologs from a large number of taxa. Nevertheless, Mutual Information-based distances proved to be useful in analyzing this kind of data, also because the estimation of MI-based distances is independent of evolutionary models and therefore no pre-definitions of ancestral and derived character states are necessary.}, language = {en} } @article{KetmaierMarroneAlfonsoetal.2012, author = {Ketmaier, Valerio and Marrone, Federico and Alfonso, Giuseppe and Paulus, Kirsten B. and Wiemann, Annika and Tiedemann, Ralph and Mura, Graziella}, title = {Mitochondrial DNA regionalism and historical demography in the extant populations of chirocephalus kerkyrensis (Branchiopoda: Anostraca)}, series = {PLoS one}, volume = {7}, journal = {PLoS one}, number = {2}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0030082}, pages = {11}, year = {2012}, abstract = {Background: Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. Methodology/Principal Findings: We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (approximate to 81\%) is apportioned among the aforementioned lineages. Conclusions/Significance: Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies.}, language = {en} } @article{KiemelDeCahsanParaskevopoulouetal.2022, author = {Kiemel, Katrin and De Cahsan, Binia and Paraskevopoulou, Sofia and Weithoff, Guntram and Tiedemann, Ralph}, title = {Mitochondrial genomes of the freshwater monogonont rotifer Brachionus fernandoi and of two additional B. calyciflorus sensu stricto lineages from Germany and the USA (Rotifera, Brachionidae)}, series = {Mitochondrial DNA. Part B-Resources}, volume = {7}, journal = {Mitochondrial DNA. Part B-Resources}, number = {4}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {2380-2359}, doi = {10.1080/23802359.2022.2060765}, pages = {646 -- 648}, year = {2022}, abstract = {The Brachionus calyciflorus species complex was recently subdivided into four species, but genetic resources to resolve phylogenetic relationships within this complex are still lacking. We provide two complete mitochondrial (mt) genomes from B. calyciflorus sensu stricto (Germany, USA) and the mt coding sequences (cds) from a German B. fernandoi. Phylogenetic analysis placed our B. calyciflorus sensu stricto strains close to the published genomes of B. calyciflorus, forming the putative sister species to B. fernandoi. Global representatives of B. calyciflorus sensu stricto (i.e. Europe, USA, and China) are genetically closer related to each other than to B. fernandoi (average pairwise nucleotide diversity 0.079 intraspecific vs. 0.254 interspecific).}, language = {en} } @article{KiemelGurkeParaskevopoulouetal.2022, author = {Kiemel, Katrin and Gurke, Marie and Paraskevopoulou, Sofia and Havenstein, Katja and Weithoff, Guntram and Tiedemann, Ralph}, title = {Variation in heat shock protein 40 kDa relates to divergence in thermotolerance among cryptic rotifer species}, series = {Scientific reports}, volume = {12}, journal = {Scientific reports}, number = {1}, publisher = {Macmillan Publishers Limited}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-022-27137-3}, pages = {14}, year = {2022}, abstract = {Genetic divergence and the frequency of hybridization are central for defining species delimitations, especially among cryptic species where morphological differences are merely absent. Rotifers are known for their high cryptic diversity and therefore are ideal model organisms to investigate such patterns. Here, we used the recently resolved Brachionus calyciflorus species complex to investigate whether previously observed between species differences in thermotolerance and gene expression are also reflected in their genomic footprint. We identified a Heat Shock Protein gene (HSP 40 kDa) which exhibits cross species pronounced sequence variation. This gene exhibits species-specific fixed sites, alleles, and sites putatively under positive selection. These sites are located in protein binding regions involved in chaperoning and may therefore reflect adaptive diversification. By comparing three genetic markers (ITS, COI, HSP 40 kDa), we revealed hybridization events between the cryptic species. The low frequency of introgressive haplotypes/alleles suggest a tight, but not fully impermeable boundary between the cryptic species.}, language = {en} } @misc{KiemelGurkeParaskevopoulouetal.2022, author = {Kiemel, Katrin and Gurke, Marie and Paraskevopoulou, Sofia and Havenstein, Katja and Weithoff, Guntram and Tiedemann, Ralph}, title = {Variation in heat shock protein 40 kDa relates to divergence in thermotolerance among cryptic rotifer species}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1305}, issn = {1866-8372}, doi = {10.25932/publishup-57863}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-578635}, pages = {14}, year = {2022}, abstract = {Genetic divergence and the frequency of hybridization are central for defining species delimitations, especially among cryptic species where morphological differences are merely absent. Rotifers are known for their high cryptic diversity and therefore are ideal model organisms to investigate such patterns. Here, we used the recently resolved Brachionus calyciflorus species complex to investigate whether previously observed between species differences in thermotolerance and gene expression are also reflected in their genomic footprint. We identified a Heat Shock Protein gene (HSP 40 kDa) which exhibits cross species pronounced sequence variation. This gene exhibits species-specific fixed sites, alleles, and sites putatively under positive selection. These sites are located in protein binding regions involved in chaperoning and may therefore reflect adaptive diversification. By comparing three genetic markers (ITS, COI, HSP 40 kDa), we revealed hybridization events between the cryptic species. The low frequency of introgressive haplotypes/alleles suggest a tight, but not fully impermeable boundary between the cryptic species.}, language = {en} } @article{KiemelGurkeParaskevopoulouetal.2022, author = {Kiemel, Katrin and Gurke, Marie and Paraskevopoulou, Sofia and Havenstein, Katja and Weithoff, Guntram and Tiedemann, Ralph}, title = {Variation in heat shock protein 40 kDa relates to divergence in thermotolerance among cryptic rotifer species}, series = {Scientific Reports}, volume = {12}, journal = {Scientific Reports}, publisher = {Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-022-27137-3}, pages = {14}, year = {2022}, abstract = {Genetic divergence and the frequency of hybridization are central for defining species delimitations, especially among cryptic species where morphological differences are merely absent. Rotifers are known for their high cryptic diversity and therefore are ideal model organisms to investigate such patterns. Here, we used the recently resolved Brachionus calyciflorus species complex to investigate whether previously observed between species differences in thermotolerance and gene expression are also reflected in their genomic footprint. We identified a Heat Shock Protein gene (HSP 40 kDa) which exhibits cross species pronounced sequence variation. This gene exhibits species-specific fixed sites, alleles, and sites putatively under positive selection. These sites are located in protein binding regions involved in chaperoning and may therefore reflect adaptive diversification. By comparing three genetic markers (ITS, COI, HSP 40 kDa), we revealed hybridization events between the cryptic species. The low frequency of introgressive haplotypes/alleles suggest a tight, but not fully impermeable boundary between the cryptic species.}, language = {en} } @article{KiemelWeithoffTiedemann2022, author = {Kiemel, Katrin and Weithoff, Guntram and Tiedemann, Ralph}, title = {DNA metabarcoding reveals impact of local recruitment, dispersal, and hydroperiod on assembly of a zooplankton metacommunity}, series = {Molecular ecology}, volume = {32}, journal = {Molecular ecology}, number = {23}, publisher = {Wiley}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.16627}, pages = {20}, year = {2022}, abstract = {Understanding the environmental impact on the assembly of local communities in relation to their spatial and temporal connectivity is still a challenge in metacommunity ecology. This study aims to unravel underlying metacommunity processes and environmental factors that result in observed zooplankton communities. Unlike most metacommunity studies, we jointly examine active and dormant zooplankton communities using a DNA metabarcoding approach to overcome limitations of morphological species identification. We applied two-fragment (COI and 18S) metabarcoding to monitor communities of 24 kettle holes over a two-year period to unravel (i) spatial and temporal connectivity of the communities, (ii) environmental factors influencing local communities, and (iii) dominant underlying metacommunity processes in this system. We found a strong separation of zooplankton communities from kettle holes of different hydroperiods (degree of permanency) throughout the season, while the community composition within single kettle holes did not differ between years. Species richness was primarily dependent on pH and permanency, while species diversity (Shannon Index) was influenced by kettle hole location. Community composition was impacted by kettle hole size and surrounding field crops. Environmental processes dominated temporal and spatial processes. Sediment communities showed a different composition compared to water samples but did not differ between ephemeral and permanent kettle holes. Our results suggest that communities are mainly structured by environmental filtering based on pH, kettle hole size, surrounding field crops, and permanency. Environmental filtering based on specific conditions in individual kettle holes seems to be the dominant process in community assembly in the studied zooplankton metacommunity.}, language = {en} } @article{KorniienkoNguyenBaumgartneretal.2020, author = {Korniienko, Yevheniia and Nguyen, Linh and Baumgartner, Stephanie and Vater, Marianne and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua male x C. compressirostris female) are fertile}, series = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {206}, journal = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, number = {4}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-7594}, doi = {10.1007/s00359-020-01425-7}, pages = {571 -- 585}, year = {2020}, abstract = {Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids betweenCampylomormyrus tamandua male x C. compressirostris female were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12-13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8\%. Eggs started to hatch 70-72 h after fertilization, average hatching rate was 95.6\%. Average mortality rate during embryonic development amounted to 2.3\%. Average malformation rate during the free embryonic stage was 27.7\%. Exogenous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically.}, language = {en} } @article{KorniienkoNguyenBaumgartneretal.2021, author = {Korniienko, Yevheniia and Nguyen, Linh and Baumgartner, Stephanie and Vater, Marianne and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Correction to: Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua male x C. compressirostris female) are fertile (vol 206, pg 571, 2020)}, series = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {207}, journal = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, number = {6}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-7594}, doi = {10.1007/s00359-021-01513-2}, pages = {773 -- 773}, year = {2021}, language = {en} } @article{KorniienkoTiedemannVateretal.2020, author = {Korniienko, Yevheniia and Tiedemann, Ralph and Vater, Marianne and Kirschbaum, Frank}, title = {Ontogeny of the electric organ discharge and of the papillae of the electrocytes in the weakly electric fish Campylomormyrus rhynchophorus (Teleostei: Mormyridae)}, series = {The journal of comparative neurology}, volume = {529}, journal = {The journal of comparative neurology}, number = {5}, publisher = {Wiley}, address = {Hoboken}, issn = {0021-9967}, doi = {10.1002/cne.25003}, pages = {1052 -- 1065}, year = {2020}, abstract = {The electric organ of the mormyrid weakly electric fish,Campylomormyrus rhynchophorus(Boulenger, 1898), undergoes changes in both the electric organ discharge (EOD) and the light and electron microscopic morphology as the fish mature from the juvenile to the adult form. Of particular interest was the appearance of papillae, surface specializations of the uninnervated anterior face of the electrocyte, which have been hypothesized to increase the duration of the EOD. In a 24.5 mm long juvenile the adult electric organ (EO) was not yet functional, and the electrocytes lacked papillae. A 40 mm long juvenile, which produced a short biphasic EOD of 1.3 ms duration, shows small papillae (average area 136 mu m(2)). In contrast, the EOD of a 79 mm long juvenile was triphasic. The large increase in duration of the EOD to 23.2 ms was accompanied by a small change in size of the papillae (average area 159 mu m(2)). Similarly, a 150 mm long adult produced a triphasic EOD of comparable duration to the younger stage (24.7 ms) but featured a prominent increase in size of the papillae (average area 402 mu m(2)). Thus, there was no linear correlation between EOD duration and papillary size. The most prominent ultrastructural change was at the level of the myofilaments, which regularly extended into the papillae, only in the oldest specimen-probably serving a supporting function. Physiological mechanisms, like gene expression levels, as demonstrated in someCampylomormyrusspecies, might be more important concerning the duration of the EOD.}, language = {en} } @article{KruegerFoersterTrauthetal.2021, author = {Kr{\"u}ger, Johanna and Foerster, Verena Elisabeth and Trauth, Martin H. and Hofreiter, Michael and Tiedemann, Ralph}, title = {Exploring the Past Biosphere of Chew Bahir/Southern Ethiopia: Cross-Species Hybridization Capture of Ancient Sedimentary DNA from a Deep Drill Core}, series = {Frontiers in Earth Science}, journal = {Frontiers in Earth Science}, publisher = {Frontiers in Earth Science}, address = {Lausanne, Schweiz}, issn = {2296-6463}, doi = {10.3389/feart.2021.683010}, pages = {1 -- 20}, year = {2021}, abstract = {Eastern Africa has been a prime target for scientific drilling because it is rich in key paleoanthropological sites as well as in paleolakes, containing valuable paleoclimatic information on evolutionary time scales. The Hominin Sites and Paleolakes Drilling Project (HSPDP) explores these paleolakes with the aim of reconstructing environmental conditions around critical episodes of hominin evolution. Identification of biological taxa based on their sedimentary ancient DNA (sedaDNA) traces can contribute to understand past ecological and climatological conditions of the living environment of our ancestors. However, sedaDNA recovery from tropical environments is challenging because high temperatures, UV irradiation, and desiccation result in highly degraded DNA. Consequently, most of the DNA fragments in tropical sediments are too short for PCR amplification. We analyzed sedaDNA in the upper 70 m of the composite sediment core of the HSPDP drill site at Chew Bahir for eukaryotic remnants. We first tested shotgun high throughput sequencing which leads to metagenomes dominated by bacterial DNA of the deep biosphere, while only a small fraction was derived from eukaryotic, and thus probably ancient, DNA. Subsequently, we performed cross-species hybridization capture of sedaDNA to enrich ancient DNA (aDNA) from eukaryotic remnants for paleoenvironmental analysis, using established barcoding genes (cox1 and rbcL for animals and plants, respectively) from 199 species that may have had relatives in the past biosphere at Chew Bahir. Metagenomes yielded after hybridization capture are richer in reads with similarity to cox1 and rbcL in comparison to metagenomes without prior hybridization capture. Taxonomic assignments of the reads from these hybridization capture metagenomes also yielded larger fractions of the eukaryotic domain. For reads assigned to cox1, inferred wet periods were associated with high inferred relative abundances of putative limnic organisms (gastropods, green algae), while inferred dry periods showed increased relative abundances for insects. These findings indicate that cross-species hybridization capture can be an effective approach to enhance the information content of sedaDNA in order to explore biosphere changes associated with past environmental conditions, enabling such analyses even under tropical conditions.}, language = {en} } @misc{KruegerFoersterTrauthetal.2021, author = {Kr{\"u}ger, Johanna and Foerster, Verena Elisabeth and Trauth, Martin H. and Hofreiter, Michael and Tiedemann, Ralph}, title = {Exploring the Past Biosphere of Chew Bahir/Southern Ethiopia: Cross-Species Hybridization Capture of Ancient Sedimentary DNA from a Deep Drill Core}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8372}, doi = {10.25932/publishup-55007}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-550071}, pages = {1 -- 20}, year = {2021}, abstract = {Eastern Africa has been a prime target for scientific drilling because it is rich in key paleoanthropological sites as well as in paleolakes, containing valuable paleoclimatic information on evolutionary time scales. The Hominin Sites and Paleolakes Drilling Project (HSPDP) explores these paleolakes with the aim of reconstructing environmental conditions around critical episodes of hominin evolution. Identification of biological taxa based on their sedimentary ancient DNA (sedaDNA) traces can contribute to understand past ecological and climatological conditions of the living environment of our ancestors. However, sedaDNA recovery from tropical environments is challenging because high temperatures, UV irradiation, and desiccation result in highly degraded DNA. Consequently, most of the DNA fragments in tropical sediments are too short for PCR amplification. We analyzed sedaDNA in the upper 70 m of the composite sediment core of the HSPDP drill site at Chew Bahir for eukaryotic remnants. We first tested shotgun high throughput sequencing which leads to metagenomes dominated by bacterial DNA of the deep biosphere, while only a small fraction was derived from eukaryotic, and thus probably ancient, DNA. Subsequently, we performed cross-species hybridization capture of sedaDNA to enrich ancient DNA (aDNA) from eukaryotic remnants for paleoenvironmental analysis, using established barcoding genes (cox1 and rbcL for animals and plants, respectively) from 199 species that may have had relatives in the past biosphere at Chew Bahir. Metagenomes yielded after hybridization capture are richer in reads with similarity to cox1 and rbcL in comparison to metagenomes without prior hybridization capture. Taxonomic assignments of the reads from these hybridization capture metagenomes also yielded larger fractions of the eukaryotic domain. For reads assigned to cox1, inferred wet periods were associated with high inferred relative abundances of putative limnic organisms (gastropods, green algae), while inferred dry periods showed increased relative abundances for insects. These findings indicate that cross-species hybridization capture can be an effective approach to enhance the information content of sedaDNA in order to explore biosphere changes associated with past environmental conditions, enabling such analyses even under tropical conditions.}, language = {en} } @article{LahTrenseBenkeetal.2016, author = {Lah, Ljerka and Trense, Daronja and Benke, Harald and Berggren, Per and Gunnlaugsson, Porvaldur and Lockyer, Christina and {\"O}zt{\"u}rk, Ayaka and {\"O}zt{\"u}rk, Bayram and Pawliczka, Iwona and Roos, Anna and Siebert, Ursula and Skora, Krzysztof and Vikingsson, Gisli and Tiedemann, Ralph}, title = {Spatially Explicit Analysis of Genome-Wide SNPs Detects Subtle Population Structure in a Mobile Marine Mammal, the Harbor Porpoise}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0162792}, pages = {23}, year = {2016}, abstract = {The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymor-phisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.}, language = {en} } @article{LahTrenseBenkeetal.2016, author = {Lah, Ljerka and Trense, Daronja and Benke, Harald and Berggren, Per and Gunnlaugsson, Þorvaldur and Lockyer, Christina and {\"O}zt{\"u}rk, Ayaka and {\"O}zt{\"u}rk, Bayram and Pawliczka, Iwona and Roos, Anna and Siebert, Ursula and Sk{\´o}ra, Krzysztof and V{\´i}kingsson, G{\´i}sli and Tiedemann, Ralph}, title = {Spatially Explicit Analysis of Genome-Wide SNPs Detects Subtle Population Structure in a Mobile Marine Mammal, the Harbor Porpoise}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, number = {10}, publisher = {PLoS}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0162792}, pages = {23 Seiten}, year = {2016}, abstract = {The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymorphisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.}, language = {en} } @misc{LahTrenseBenkeetal.2016, author = {Lah, Ljerka and Trense, Daronja and Benke, Harald and Berggren, Per and Gunnlaugsson, Þorvaldur and Lockyer, Christina and {\"O}zt{\"u}rk, Ayaka and {\"O}zt{\"u}rk, Bayram and Pawliczka, Iwona and Roos, Anna and Siebert, Ursula and Sk{\´o}ra, Krzysztof and V{\´i}kingsson, G{\´i}sli and Tiedemann, Ralph}, title = {Spatially Explicit Analysis of Genome-Wide SNPs Detects Subtle Population Structure in a Mobile Marine Mammal, the Harbor Porpoise}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100813}, pages = {23 Seiten}, year = {2016}, abstract = {The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymorphisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.}, language = {en} } @article{LamannaKirschbaumErnstetal.2016, author = {Lamanna, Francesco and Kirschbaum, Frank and Ernst, Anja R. R. and Feulner, Philine G. D. and Mamonekene, Victor and Paul, Christiane and Tiedemann, Ralph}, title = {Species delimitation and phylogenetic relationships in a genus of African weakly-electric fishes (Osteoglossiformes, Mormyridae, Campylomormyrus)}, series = {Molecular phylogenetics and evolution}, volume = {101}, journal = {Molecular phylogenetics and evolution}, publisher = {Elsevier}, address = {San Diego}, issn = {1055-7903}, doi = {10.1016/j.ympev.2016.04.035}, pages = {8 -- 18}, year = {2016}, abstract = {African weakly-electric fishes (Mormyridae) are able to communicate through species-specific electric signals; this feature might have favoured the evolutionary radiation observed in this family (over 200 species) by acting as an effective pre-zygotic isolation mechanism. In the present study we used mitochondria((cytb) and nuclear (rps7, scn4aa) markers in order to reconstruct a species-phylogeny and identify species boundaries for the genus Campylomormyrus, by applying inference methods based on the multispecies coalescent model. Additionally, we employed 16 microsatellite markers, landmark-based morphometric measurements, and electro-physiological analyses as independent lines of evidence to the results obtained from the sequence data. The results show that groups that are morphologically different are also significantly divergent at the genetic level, whereas morphologically similar groups, displaying dissimilar electric signals, do not show enough genetic diversity to be considered separate species. Furthermore, the data confirm the presence of a yet undescribed species within the genus Campylomormyrus. (C) 2016 Elsevier Inc. All rights reserved.}, language = {en} } @article{LamannaKirschbaumTiedemann2014, author = {Lamanna, Francesco and Kirschbaum, Frank and Tiedemann, Ralph}, title = {De novo assembly and characterization of the skeletal muscle and electric organ transcriptomes of the African weakly electric fish Campylomormyrus compressirostris (Mormyridae, Teleostei)}, series = {Molecular ecology resources}, volume = {14}, journal = {Molecular ecology resources}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1755-098X}, doi = {10.1111/1755-0998.12260}, pages = {1222 -- 1230}, year = {2014}, abstract = {African weakly electric fishes (Mormyridae) underwent an outstanding adaptive radiation (about 200 species), putatively owing to their ability to communicate through species-specific weak electric signals. The electric organ discharge (EOD) is produced by muscle-derived electrocytes organized in piles to form an electric organ. Despite the importance of this trait as a prezygotic isolation mechanism, genomic resources remained limited. We present here a first draft of the skeletal muscle and electric organ transcriptomes from the weakly electric fish species Campylomormyrus compressirostris, obtained using the Illumina HiSeq2000 sequencing technology. Approximately 6.8 Gbp of cDNA sequence data were produced from both tissues, resulting in 57268109 raw reads for the skeletal muscle and 46934923 for the electric organ, and assembled de novo into 46143 and 89270 contigs, respectively. About 50\% of both transcriptomes were annotated after protein databases search. The two transcriptomes show similar profiles in terms of Gene Ontology categories composition. We identified several candidate genes which are likely to play a central role in the production and evolution of the electric signal. For most of these genes, and for many other housekeeping genes, we were able to obtain the complete or partial coding DNA sequences (CDS), which can be used for the development of primers to be utilized in qRT-PCR experiments. We present also the complete mitochondrial genome and compare it to those available from other weakly electric fish species. Additionally, we located 1671 SSR-containing regions with their flanking sites and designed the relative primers. This study establishes a first step in the development of genomic tools aimed at understanding the role of electric communication during speciation.}, language = {en} } @misc{LamannaKirschbaumWauricketal.2015, author = {Lamanna, Francesco and Kirschbaum, Frank and Waurick, Isabelle and Dieterich, Christoph and Tiedemann, Ralph}, title = {Cross-tissue and cross-species analysis of gene expression in skeletal muscle and electric organ of African weakly-electric fish (Teleostei; Mormyridae)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86997}, year = {2015}, abstract = {Background African weakly-electric fishes of the family Mormyridae are able to produce and perceive weak electric signals (typically less than one volt in amplitude) owing to the presence of a specialized, muscle-derived electric organ (EO) in their tail region. Such electric signals, also known as Electric Organ Discharges (EODs), are used for objects/prey localization, for the identification of conspecifics, and in social and reproductive behaviour. This feature might have promoted the adaptive radiation of this family by acting as an effective pre-zygotic isolation mechanism. Despite the physiological and evolutionary importance of this trait, the investigation of the genetic basis of its function and modification has so far remained limited. In this study, we aim at: i) identifying constitutive differences in terms of gene expression between electric organ and skeletal muscle (SM) in two mormyrid species of the genus Campylomormyrus: C. compressirostris and C. tshokwe, and ii) exploring cross-specific patterns of gene expression within the two tissues among C. compressirostris, C. tshokwe, and the outgroup species Gnathonemus petersii. Results Twelve paired-end (100 bp) strand-specific RNA-seq Illumina libraries were sequenced, producing circa 330 M quality-filtered short read pairs. The obtained reads were assembled de novo into four reference transcriptomes. In silico cross-tissue DE-analysis allowed us to identify 271 shared differentially expressed genes between EO and SM in C. compressirostris and C.tshokwe. Many of these genes correspond to myogenic factors, ion channels and pumps, and genes involved in several metabolic pathways. Cross-species analysis has revealed that the electric organ transcriptome is more variable in terms of gene expression levels across species than the skeletal muscle transcriptome. Conclusions The data obtained indicate that: i) the loss of contractile activity and the decoupling of the excitation-contraction processes are reflected by the down-regulation of the corresponding genes in the electric organ's transcriptome; ii) the metabolic activity of the EO might be specialized towards the production and turn-over of membrane structures; iii) several ion channels are highly expressed in the EO in order to increase excitability; iv) several myogenic factors might be down-regulated by transcription repressors in the EO.}, language = {en} } @article{LamannaKirschbaumWauricketal.2015, author = {Lamanna, Francesco and Kirschbaum, Frank and Waurick, Isabelle and Dieterich, Christoph and Tiedemann, Ralph}, title = {Cross-tissue and cross-species analysis of gene expression in skeletal muscle and electric organ of African weakly-electric fish (Teleostei; Mormyridae)}, series = {BMC genomics}, volume = {16}, journal = {BMC genomics}, publisher = {BioMed Central}, address = {London}, issn = {1471-2164}, doi = {10.1186/s12864-015-1858-9}, pages = {17}, year = {2015}, abstract = {Background: African weakly-electric fishes of the family Mormyridae are able to produce and perceive weak electric signals (typically less than one volt in amplitude) owing to the presence of a specialized, muscle-derived electric organ (EO) in their tail region. Such electric signals, also known as Electric Organ Discharges (EODs), are used for objects/prey localization, for the identification of conspecifics, and in social and reproductive behaviour. This feature might have promoted the adaptive radiation of this family by acting as an effective pre-zygotic isolation mechanism. Despite the physiological and evolutionary importance of this trait, the investigation of the genetic basis of its function and modification has so far remained limited. In this study, we aim at: i) identifying constitutive differences in terms of gene expression between electric organ and skeletal muscle (SM) in two mormyrid species of the genus Campylomormyrus: C. compressirostris and C. tshokwe, and ii) exploring cross-specific patterns of gene expression within the two tissues among C. compressirostris, C. tshokwe, and the outgroup species Gnathonemus petersii. Results: Twelve paired-end (100 bp) strand-specific RNA-seq Illumina libraries were sequenced, producing circa 330 M quality-filtered short read pairs. The obtained reads were assembled de novo into four reference transcriptomes. In silico cross-tissue DE-analysis allowed us to identify 271 shared differentially expressed genes between EO and SM in C. compressirostris and C. tshokwe. Many of these genes correspond to myogenic factors, ion channels and pumps, and genes involved in several metabolic pathways. Cross-species analysis has revealed that the electric organ transcriptome is more variable in terms of gene expression levels across species than the skeletal muscle transcriptome. Conclusions: The data obtained indicate that: i) the loss of contractile activity and the decoupling of the excitation-contraction processes are reflected by the down-regulation of the corresponding genes in the electric organ's transcriptome; ii) the metabolic activity of the EO might be specialized towards the production and turn-over of membrane structures; iii) several ion channels are highly expressed in the EO in order to increase excitability; iv) several myogenic factors might be down-regulated by transcription repressors in the EO.}, language = {en} } @article{LamannaKirschbaumWauricketal.2015, author = {Lamanna, Francesco and Kirschbaum, Frank and Waurick, Isabelle and Dieterich, Christoph and Tiedemann, Ralph}, title = {Cross-tissue and cross-species analysis of gene expression in skeletal muscle and electric organ of African weakly-electric fish (Teleostei; Mormyridae)}, series = {BMC Genomics}, volume = {16}, journal = {BMC Genomics}, number = {668}, publisher = {Biomed Central}, address = {London}, issn = {1471-2164}, doi = {10.1186/s12864-015-1858-9}, year = {2015}, abstract = {Background African weakly-electric fishes of the family Mormyridae are able to produce and perceive weak electric signals (typically less than one volt in amplitude) owing to the presence of a specialized, muscle-derived electric organ (EO) in their tail region. Such electric signals, also known as Electric Organ Discharges (EODs), are used for objects/prey localization, for the identification of conspecifics, and in social and reproductive behaviour. This feature might have promoted the adaptive radiation of this family by acting as an effective pre-zygotic isolation mechanism. Despite the physiological and evolutionary importance of this trait, the investigation of the genetic basis of its function and modification has so far remained limited. In this study, we aim at: i) identifying constitutive differences in terms of gene expression between electric organ and skeletal muscle (SM) in two mormyrid species of the genus Campylomormyrus: C. compressirostris and C. tshokwe, and ii) exploring cross-specific patterns of gene expression within the two tissues among C. compressirostris, C. tshokwe, and the outgroup species Gnathonemus petersii. Results Twelve paired-end (100 bp) strand-specific RNA-seq Illumina libraries were sequenced, producing circa 330 M quality-filtered short read pairs. The obtained reads were assembled de novo into four reference transcriptomes. In silico cross-tissue DE-analysis allowed us to identify 271 shared differentially expressed genes between EO and SM in C. compressirostris and C.tshokwe. Many of these genes correspond to myogenic factors, ion channels and pumps, and genes involved in several metabolic pathways. Cross-species analysis has revealed that the electric organ transcriptome is more variable in terms of gene expression levels across species than the skeletal muscle transcriptome. Conclusions The data obtained indicate that: i) the loss of contractile activity and the decoupling of the excitation-contraction processes are reflected by the down-regulation of the corresponding genes in the electric organ's transcriptome; ii) the metabolic activity of the EO might be specialized towards the production and turn-over of membrane structures; iii) several ion channels are highly expressed in the EO in order to increase excitability; iv) several myogenic factors might be down-regulated by transcription repressors in the EO.}, language = {en} } @article{MahlerSchneiderDiGiacomoetal.2013, author = {Mahler, B. and Schneider, A. R. R. and Di Giacomo, A. S. and Di Giacomo, A. G. and Reboreda, Juan C. and Tiedemann, Ralph}, title = {Microsatellite usefulness is independent of phylogenetic distance in Tyrant flycatchers (Aves: Tyrannidae) - a test using two globally threatened species}, series = {Genetics and molecular research}, volume = {12}, journal = {Genetics and molecular research}, number = {3}, publisher = {FUNPEC}, address = {Ribeirao Preto}, issn = {1676-5680}, doi = {10.4238/2013.August.12.12}, pages = {2966 -- 2972}, year = {2013}, abstract = {Tyrant flycatchers (Aves: Tyrannidae) are endemic to the New World, and many species of this group are threatened or near-threatened at the global level. The aim of this study was to test the 18 microsatellite markers that have been published for other Tyrant flycatchers in the Strange-tailed Tyrant (Alectrurus risora) and the Sharp-tailed Tyrant (Culicivora caudacuta), two endemic species of southern South American grasslands that are classified as vulnerable. We also analyzed the usefulness of loci in relation to phylogenetic distance to the source species. Amplification success was high in both species (77 to 83\%) and did not differ between the more closely and more distantly related species to the source species. Polymorphism success was also similar for both species, with 9 and 8 loci being polymorphic, respectively. An increased phylogenetic distance thus does not gradually lead to allelic or locus dropouts, implying that in Tyrant flycatchers, the published loci are useful independent of species relatedness.}, language = {en} } @article{MakowiczTiedemannSteeleetal.2016, author = {Makowicz, Amber M. and Tiedemann, Ralph and Steele, Rachel N. and Schlupp, Ingo}, title = {Kin Recognition in a Clonal Fish, Poecilia formosa}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0158442}, pages = {20}, year = {2016}, abstract = {Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50\% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.}, language = {en} } @article{MarroneHavensteinTiedemannetal.2016, author = {Marrone, F. and Havenstein, Katja and Tiedemann, Ralph and Ketmaier, V.}, title = {Identification and characterization of five polymorphic microsatellite loci in the freshwater copepod Hemidiaptomus gurneyi (Copepoda: Calanoida: Diaptomidae)}, series = {The Italian journal of zoology}, volume = {83}, journal = {The Italian journal of zoology}, publisher = {Springer}, address = {Abingdon}, issn = {1125-0003}, doi = {10.1080/11250003.2015.1126363}, pages = {146 -- 150}, year = {2016}, abstract = {Hemidiaptomus diaptomid copepods are known to be excellent biological indicators for the highly biodiverse crustacean communities inhabiting Mediterranean temporary ponds (MTPs), an endangered inland water habitat whose conservation is considered a priority according to the "Habitat Directive" of the European Union. This study reports on the characterization of five polymorphic microsatellite loci in Hemidiaptomus gurneyi, to be used as markers for fine-scale studies on the population genetic structure and metapopulation dynamics of a typical and obligate MTP dweller. The five selected loci proved to be polymorphic in the species, with three to five polymorphic loci per studied population. Overall, mean heterozygosity scored for all loci and populations was lower than that reported for the few other diaptomid species for which microsatellite loci have been to date described; this is possibly due to the intrinsically fragmented and isolated peculiar habitat inhabited by the species. Furthermore, the presence of indels within the flanking regions of selected loci was scored. This study, albeit confirming the technical difficulties in finding proper microsatellite markers in copepods, provides for the first time a set of useful polymorphic microsatellite loci for a Hemidiaptomus species, thus allowing the realization of fine-scale phylogeographic and population genetics studies of this flagship crustacean taxon for MTPs.}, language = {en} } @article{MilinkovitchMonteyneGibbsetal.2004, author = {Milinkovitch, M. C. and Monteyne, D. and Gibbs, J. P. and Fritts, T. H. and Tapia, W. and Snell, H. L. and Tiedemann, Ralph and Caccone, Adalgisa and Powell, J. R.}, title = {Genetic analysis of a successful repatriation programme : giant Galapagos tortoises}, issn = {0962-8452}, year = {2004}, abstract = {As natural populations of endangered species dwindle to precarious levels, remaining members are sometimes brought into captivity, allowed to breed and their offspring returned to the natural habitat. One goal of such repatriation programmes is to retain as much of the genetic variation of the species as possible. A taxon of giant GalApagos tortoises on the island of Espahola has been the subject of a captive breeding-repatriation programme for 33 years. Core breeders, consisting of 12 females and three males, have produced more than 1200 offspring that have been released on Espanola where in situ reproduction has recently been observed. Using microsatellite DNA markers, we have determined the maternity and paternity of 132 repatriated offspring. Contributions of the breeders are highly skewed. This has led to a further loss of genetic variation that is detrimental to the long-term survival of the population. Modifications to the breeding programme could alleviate this problem}, language = {en} } @article{MilinkovitchKanitzTiedemannetal.2013, author = {Milinkovitch, Michel C. and Kanitz, Ricardo and Tiedemann, Ralph and Tapia, Washington and Llerena, Fausto and Caccone, Adalgisa and Gibbs, James P. and Powell, Jeffrey R.}, title = {Recovery of a nearly extinct Galapagos tortoise despite minimal genetic variation}, series = {Evolutionary applications}, volume = {6}, journal = {Evolutionary applications}, number = {2}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1752-4571}, doi = {10.1111/eva.12014}, pages = {377 -- 383}, year = {2013}, abstract = {A species of Galapagos tortoise endemic to Espanola Island was reduced to just 12 females and three males that have been bred in captivity since 1971 and have produced over 1700 offspring now repatriated to the island. Our molecular genetic analyses of juveniles repatriated to and surviving on the island indicate that none of the tortoises sampled in 1994 had hatched on the island versus 3\% in 2004 and 24\% in 2007, which demonstrates substantial and increasing reproduction in situ once again. This recovery occurred despite the parental population having an estimated effective population size <8 due to a combination of unequal reproductive success of the breeders and nonrandom mating in captivity. These results provide guidelines for adapting breeding regimes in the parental captive population and decreasing inbreeding in the repatriated population. Using simple morphological data scored on the sampled animals, we also show that a strongly heterogeneous distribution of tortoise sizes on Espanola Island observed today is due to a large variance in the number of animals included in yearly repatriation events performed in the last 40years. Our study reveals that, at least in the short run, some endangered species can recover dramatically despite a lack of genetic variation and irregular repatriation efforts.}, language = {en} } @article{NagelKirschbaumHofmannetal.2018, author = {Nagel, Rebecca and Kirschbaum, Frank and Hofmann, Volker and Engelmann, Jacob and Tiedemann, Ralph}, title = {Electric pulse characteristics can enable species recognition in African weakly electric fish species}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-018-29132-z}, pages = {1 -- 12}, year = {2018}, abstract = {Communication is key to a wide variety of animal behaviours and multiple modalities are often involved in this exchange of information from sender to receiver. The communication of African weakly electric fish, however, is thought to be predominantly unimodal and is mediated by their electric sense, in which species-specific electric organ discharges (EODs) are generated in a context-dependent and thus variable sequence of pulse intervals (SPI). While the primary function of the electric sense is considered to be electrolocation, both of its components likely carry information regarding identity of the sender. However, a clear understanding of their contribution to species recognition is incomplete. We therefore analysed these two electrocommunication components (EOD waveform and SPI statistics) in two sympatric mormyrid Campylomormyrus species. In a set of five playback conditions, we further investigated which components may drive interspecific recognition and discrimination. While we found that both electrocommunication components are species-specific, the cues necessary for species recognition differ between the two species studied. While the EOD waveform and SPI were both necessary and sufficient for species recognition in C. compressirostris males, C. tamandua males apparently utilize other, non-electric modalities. Mapped onto a recent phylogeny, our results suggest that discrimination by electric cues alone may be an apomorphic trait evolved during a recent radiation in this taxon.}, language = {en} } @misc{NagelKirschbaumHofmannetal.2018, author = {Nagel, Rebecca and Kirschbaum, Frank and Hofmann, Volker and Engelmann, Jacob and Tiedemann, Ralph}, title = {Electric pulse characteristics can enable species recognition in African weakly electric fish species}, series = {Scientific Reports}, journal = {Scientific Reports}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-417577}, pages = {12}, year = {2018}, abstract = {Communication is key to a wide variety of animal behaviours and multiple modalities are often involved in this exchange of information from sender to receiver. The communication of African weakly electric fish, however, is thought to be predominantly unimodal and is mediated by their electric sense, in which species-specific electric organ discharges (EODs) are generated in a context-dependent and thus variable sequence of pulse intervals (SPI). While the primary function of the electric sense is considered to be electrolocation, both of its components likely carry information regarding identity of the sender. However, a clear understanding of their contribution to species recognition is incomplete. We therefore analysed these two electrocommunication components (EOD waveform and SPI statistics) in two sympatric mormyrid Campylomormyrus species. In a set of five playback conditions, we further investigated which components may drive interspecific recognition and discrimination. While we found that both electrocommunication components are species-specific, the cues necessary for species recognition differ between the two species studied. While the EOD waveform and SPI were both necessary and sufficient for species recognition in C. compressirostris males, C. tamandua males apparently utilize other, non-electric modalities. Mapped onto a recent phylogeny, our results suggest that discrimination by electric cues alone may be an apomorphic trait evolved during a recent radiation in this taxon.}, language = {en} } @article{NagelKirschbaumTiedemann2017, author = {Nagel, Rebecca and Kirschbaum, Frank and Tiedemann, Ralph}, title = {Electric organ discharge diversification in mormyrid weakly electric fish is associated with differential expression of voltage-gated ion channel genes}, series = {Journal of comparative physiology : A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {203}, journal = {Journal of comparative physiology : A, Neuroethology, sensory, neural, and behavioral physiology}, publisher = {Springer}, address = {New York}, issn = {0340-7594}, doi = {10.1007/s00359-017-1151-2}, pages = {183 -- 195}, year = {2017}, abstract = {In mormyrid weakly electric fish, the electric organ discharge (EOD) is used for species recognition, orientation and prey localization. Produced in the muscle-derived adult electric organ, the EOD exhibits a wide diversity across species in both waveform and duration. While certain defining EOD characteristics can be linked to anatomical features of the electric organ, many factors underlying EOD differentiation are yet unknown. Here, we report the differential expression of 13 Kv1 voltage-gated potassium channel genes, two inwardly rectifying potassium channel genes, two previously studied sodium channel genes and an ATPase pump in two sympatric species of the genus Campylomormyrus in both the adult electric organ and skeletal muscle. Campylomormyrus compressirostris displays a basal EOD, largely unchanged during development, while C. tshokwe has an elongated, putatively derived discharge. We report an upregulation in all Kv1 genes in the electric organ of Campylomormyrus tshokwe when compared to both skeletal muscle and C. compressirostris electric organ. This pattern of upregulation in a species with a derived EOD form suggests that voltage-gated potassium channels are potentially involved in the diversification of the EOD signal among mormyrid weakly electric fish.}, language = {en} } @article{NahavandiKetmaierPlathetal.2013, author = {Nahavandi, Nahid and Ketmaier, Valerio and Plath, Martin and Tiedemann, Ralph}, title = {Diversification of Ponto-Caspian aquatic fauna - morphology and molecules retrieve congruent evolutionary relationships in Pontogammarus maeoticus (Amphipoda: Pontogammaridae)}, series = {Molecular phylogenetics and evolution}, volume = {69}, journal = {Molecular phylogenetics and evolution}, number = {3}, publisher = {Elsevier}, address = {San Diego}, issn = {1055-7903}, doi = {10.1016/j.ympev.2013.05.021}, pages = {1063 -- 1076}, year = {2013}, abstract = {The geological history of the Ponto-Caspian region, with alternating cycles of isolation and reconnection among the three main basins (Black and Azov Seas, and the more distant Caspian Sea) as well as between them and the Mediterranean Sea, profoundly affected the diversification of its aquatic fauna, leading to a high degree of endemism. Two alternative hypotheses on the origin of this amazing biodiversity have been proposed, corresponding to phases of allopatric separation of aquatic fauna among sea basins: a Late Miocene origin (10-6 MYA) vs. a more recent Pleistocene ancestry (<2 MYA). Both hypotheses support a vicariant origin of (1) Black + Azov Sea lineages on the one hand, and (2) Caspian Sea lineages on the other. Here, we present a study on the Ponto-Caspian endemic amphipod Pontogammarus maeoticus. We assessed patterns of divergence based on (a) two mitochondrial and one nuclear gene, and (b) a morphometric analysis of 23 morphological traits in 16 populations from South and West Caspian Sea, South Azov Sea and North-West Black Sea. Genetic data indicate a long and independent evolutionary history, dating back from the late Miocene to early Pleistocene (6.6-1.6 MYA), for an unexpected, major split between (i) a Black Sea clade and (ii) a well-supported clade grouping individuals from the Caspian and Azov Seas. Absence of shared haplotypes argues against either recent or human-mediated exchanges between Caspian and Azov Seas. A mismatch distribution analysis supports more stable population demography in the Caspian than in the Black Sea populations. Morphological divergence largely followed patterns of genetic divergence: our analyses grouped samples according to the basin of origin and corroborated the close phylogenetic affinity between Caspian and Azov Sea lineages. Altogether, our results highlight the necessity of careful (group-specific) evaluation of evolutionary trajectories in marine taxa that should certainly not be inferred from the current geographical proximity of sea basins alone. (C) 2013 Elsevier Inc. All rights reserved.}, language = {en} } @article{NahavandiKetmaierTiedemann2012, author = {Nahavandi, Nahid and Ketmaier, Valerio and Tiedemann, Ralph}, title = {Intron structure of the elongation factor 1-alpha gene in the ponto-caspian amphipod pontogammarus maeoticus (Sowinsky, 1894) and its phylogeographic utility}, series = {Journal of crustacean biology}, volume = {32}, journal = {Journal of crustacean biology}, number = {3}, publisher = {Brill}, address = {San Antonio}, issn = {0278-0372}, doi = {10.1163/193724012X626584}, pages = {425 -- 433}, year = {2012}, abstract = {We tested the utility of a 230 base pair intron fragment of the highly conserved nuclear gene Elongation Factor 1-alpha (EF1-alpha) as a proper marker to reconstruct the phylogeography of the marine amphipod Pontogammarus maeoticus (Sowinsky, 1894) from the Caspian and Black Seas. As a prerequisite for further analysis, we confirmed by Southern blot analysis that EF1-alpha is encoded at a single locus in P. maeoticus. We included 15 populations and 60 individuals in the study. Both the phylogeny of the 27 unique alleles found and population genetic analyses revealed a significant differentiation between populations from the aforementioned sea basins. Our results are in remarkable agreement with recent studies on a variety of species from the same area, which invariably support a major phylogeographic break between the Caspian and Black Seas. We thus conclude that our EF1-alpha intron is an informative marker for phylogeographic studies in amphipods at the shallow population level.}, language = {en} } @article{NahavandiPlathTiedemannetal.2011, author = {Nahavandi, Nahid and Plath, Martin and Tiedemann, Ralph and Mirzajani, Ali R.}, title = {Sexual and natural selection on morphological traits in a marine amphipod, Pontogammarus maeoticus (Sowinsky, 1894)}, series = {Marine biology research}, volume = {7}, journal = {Marine biology research}, number = {2}, publisher = {Taylor \& Francis Group}, address = {Oslo}, issn = {1745-1000}, doi = {10.1080/17451001003713589}, pages = {135 -- 146}, year = {2011}, abstract = {Sexual selection often leads to sexual dimorphism, where secondary sexual traits are more expressed in the male sex. This may be due, for example, to increased fighting or mate-guarding abilities of males expressing those traits. We investigated sexually dimorphic traits in four populations of a marine amphipod, Pontogammarus maeoticus (Gammaridea: Pontogammaridae), the most abundant amphipod species in the sublittoral zone along the southern shoreline of the Caspian Sea. Male amphipods are typically larger in body size than females, and have relatively larger posterior gnathopods and antennae. However, it remains to be studied for most other body appendages whether or not, and to what extent, they are sexually dimorphic. Using Analysis of Covariance (ANCOVA), we compared the relationships between body size and trait expression for 35 metric characters between males and females, and among the four populations examined by performing three different Discriminant Function Analyses (DFA). We detected several thus far undescribed sexual dimorphic traits such as the seventh peraeopods or the epimeral plates. We also found that the size of the propodus of the first and second gnathopods increases with increasing body size, and this allometric increase was stronger in males than in females. Finally, we found that the degree of sexual dimorphism in the expression of the width of the third epimeral plate varies across sites, suggesting that differences in ecology might affect the strength of sexual selection in different populations.}, language = {en} } @misc{NeyeWallschlaegerTiedemann2006, author = {Neye, Gundula and Wallschl{\"a}ger, Hans-Dieter and Tiedemann, Ralph}, title = {Song dialect boundaries in the Yellowhammer: Do they restrict gene flow?}, series = {Journal of ornithology}, volume = {147}, journal = {Journal of ornithology}, number = {Supplement 1}, publisher = {Blackwell}, address = {New York}, issn = {0021-8375}, pages = {219 -- 219}, year = {2006}, language = {en} } @article{NguyenMamonekeneVateretal.2020, author = {Nguyen, Manh Duy Linh and Mamonekene, Victor and Vater, Marianne and Bartsch, Peter and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Ontogeny of electric organ and electric organ discharge in Campylomormyrus rhynchophorus (Teleostei: Mormyridae)}, series = {Journal of comparative physiology; A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {206}, journal = {Journal of comparative physiology; A, Neuroethology, sensory, neural, and behavioral physiology}, number = {3}, publisher = {Springer}, address = {Berlin ; Heidelberg}, issn = {0340-7594}, doi = {10.1007/s00359-020-01411-z}, pages = {453 -- 466}, year = {2020}, abstract = {The aim of this study was a longitudinal description of the ontogeny of the adult electric organ of Campylomormyrus rhynchophorus which produces as adult an electric organ discharge of very long duration (ca. 25 ms). We could indeed show (for the first time in a mormyrid fish) that the electric organ discharge which is first produced early during ontogeny in 33-mm-long juveniles is much shorter in duration and has a different shape than the electric organ discharge in 15-cm-long adults. The change from this juvenile electric organ discharges into the adult electric organ discharge takes at least a year. The increase in electric organ discharge duration could be causally linked to the development of surface evaginations, papillae, at the rostral face of the electrocyte which are recognizable for the first time in 65-mm-long juveniles and are most prominent at the periphery of the electrocyte.}, language = {en} } @article{PadurWedekindOeztuerketal.2009, author = {Padur, Lisa and Wedekind, Juliane and {\"O}zt{\"u}rk, {\"O}znur and Streit, Bruno and Tiedemann, Ralph and Plath, Martin}, title = {Do audience effects lead to relaxed male sexual harassment?}, issn = {0005-7959}, doi = {10.1163/000579509x12483520922124}, year = {2009}, abstract = {Several recent studies reported on so-called audience effects in male Atlantic mollies (Poecilia mexicana), in which the visual presence of a potential rival affects male sexual activity. We asked whether and how audience effects interact with male sexual harassment. Poecilia mexicana almost constantly attempt to mate, while females are mostly non- responsive to male approaches. Females flee from this sexual harassment and, thus, are more vigilant in the presence of males, so females may have hampered feeding opportunities. Do audience effects lead to altered male sexual harassment? Focal females were given an opportunity to feed in the presence of a male or a female partner and the difference in feeding times was interpreted as an effect caused by male harassment. Tests were conducted without an audience (1), or an audience male was visually presented either directly inside the test tank (2), or further away (in an adjoining compartment (3)). We found that levels of pre-mating behaviour did not vary significantly among treatments, but males exhibited more copulation attempts (thrusting) in treatment (3), suggesting that males respond to increased risk of sperm competition with higher sperm expenditure. Females fed less (and started feeding later) when a harassing partner male was around, and this effect was not dependent on the audience treatment, but, overall, females spent more time feeding (and started feeding earlier) when an audience was presented. Hence, feeding time reductions appear to be independent of audience effects, but perceived 'safety in numbers' may lead to increased foraging in larger groups.}, language = {en} } @misc{ParaskevopoulouDennisWeithoffetal.2019, author = {Paraskevopoulou, Sofia and Dennis, Alice B. and Weithoff, Guntram and Hartmann, Stefanie and Tiedemann, Ralph}, title = {Within species expressed genetic variability and gene expression response to different temperatures in the rotifer Brachionus calyciflorus sensu stricto}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {796}, issn = {1866-8372}, doi = {10.25932/publishup-44105}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441050}, pages = {23}, year = {2019}, abstract = {Genetic divergence is impacted by many factors, including phylogenetic history, gene flow, genetic drift, and divergent selection. Rotifers are an important component of aquatic ecosystems, and genetic variation is essential to their ongoing adaptive diversification and local adaptation. In addition to coding sequence divergence, variation in gene expression may relate to variable heat tolerance, and can impose ecological barriers within species. Temperature plays a significant role in aquatic ecosystems by affecting species abundance, spatio-temporal distribution, and habitat colonization. Recently described (formerly cryptic) species of the Brachionus calyciflorus complex exhibit different temperature tolerance both in natural and in laboratory studies, and show that B. calyciflorus sensu stricto (s.s.) is a thermotolerant species. Even within B. calyciflorus s.s., there is a tendency for further temperature specializations. Comparison of expressed genes allows us to assess the impact of stressors on both expression and sequence divergence among disparate populations within a single species. Here, we have used RNA-seq to explore expressed genetic diversity in B. calyciflorus s.s. in two mitochondrial DNA lineages with different phylogenetic histories and differences in thermotolerance. We identify a suite of candidate genes that may underlie local adaptation, with a particular focus on the response to sustained high or low temperatures. We do not find adaptive divergence in established candidate genes for thermal adaptation. Rather, we detect divergent selection among our two lineages in genes related to metabolism (lipid metabolism, metabolism of xenobiotics).}, language = {en} } @article{ParaskevopoulouDennisWeithoffetal.2019, author = {Paraskevopoulou, Sofia and Dennis, Alice B. and Weithoff, Guntram and Hartmann, Stefanie and Tiedemann, Ralph}, title = {Within species expressed genetic variability and gene expression response to different temperatures in the rotifer Brachionus calyciflorus sensu stricto}, series = {PLoS ONE}, volume = {9}, journal = {PLoS ONE}, number = {14}, publisher = {PLoS ONE}, address = {San Francisco, California}, issn = {1932-6203}, doi = {10.1371/journal.pone.0223134}, pages = {21}, year = {2019}, abstract = {Genetic divergence is impacted by many factors, including phylogenetic history, gene flow, genetic drift, and divergent selection. Rotifers are an important component of aquatic ecosystems, and genetic variation is essential to their ongoing adaptive diversification and local adaptation. In addition to coding sequence divergence, variation in gene expression may relate to variable heat tolerance, and can impose ecological barriers within species. Temperature plays a significant role in aquatic ecosystems by affecting species abundance, spatio-temporal distribution, and habitat colonization. Recently described (formerly cryptic) species of the Brachionus calyciflorus complex exhibit different temperature tolerance both in natural and in laboratory studies, and show that B. calyciflorus sensu stricto (s.s.) is a thermotolerant species. Even within B. calyciflorus s.s., there is a tendency for further temperature specializations. Comparison of expressed genes allows us to assess the impact of stressors on both expression and sequence divergence among disparate populations within a single species. Here, we have used RNA-seq to explore expressed genetic diversity in B. calyciflorus s.s. in two mitochondrial DNA lineages with different phylogenetic histories and differences in thermotolerance. We identify a suite of candidate genes that may underlie local adaptation, with a particular focus on the response to sustained high or low temperatures. We do not find adaptive divergence in established candidate genes for thermal adaptation. Rather, we detect divergent selection among our two lineages in genes related to metabolism (lipid metabolism, metabolism of xenobiotics).}, language = {en} } @article{ParaskevopoulouDennisWeithoffetal.2020, author = {Paraskevopoulou, Sofia and Dennis, Alice B. and Weithoff, Guntram and Tiedemann, Ralph}, title = {Temperature-dependent life history and transcriptomic responses in heat-tolerant versus heat-sensitive Brachionus rotifers}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, publisher = {Macmillan Publishers Limited, part of Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-020-70173-0}, pages = {15}, year = {2020}, abstract = {Thermal stress response is an essential physiological trait that determines occurrence and temporal succession in nature, including response to climate change. We compared temperature-related demography in closely related heat-tolerant and heat-sensitive Brachionus rotifer species. We found significant differences in heat response, with the heat-sensitive species adopting a strategy of long survival and low population growth, while the heat-tolerant followed the opposite strategy. In both species, we examined the genetic basis of physiological variation by comparing gene expression across increasing temperatures. Comparative transcriptomic analyses identified shared and opposing responses to heat. Interestingly, expression of heat shock proteins (hsps) was strikingly different in the two species and mirrored differences in population growth rates, showing that hsp genes are likely a key component of a species' adaptation to different temperatures. Temperature induction caused opposing patterns of expression in further functional categories including energy, carbohydrate and lipid metabolism, and in genes related to ribosomal proteins. In the heat-sensitive species, elevated temperatures caused up-regulation of genes related to meiosis induction and post-translational histone modifications. This work demonstrates the sweeping reorganizations of biological functions that accompany temperature adaptation in these two species and reveals potential molecular mechanisms that might be activated for adaptation to global warming.}, language = {en} } @misc{ParaskevopoulouDennisWeithoffetal.2020, author = {Paraskevopoulou, Sofia and Dennis, Alice B. and Weithoff, Guntram and Tiedemann, Ralph}, title = {Temperature-dependent life history and transcriptomic responses in heat-tolerant versus heat-sensitive Brachionus rotifers}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {1012}, issn = {1866-8372}, doi = {10.25932/publishup-48228}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-482280}, pages = {17}, year = {2020}, abstract = {Thermal stress response is an essential physiological trait that determines occurrence and temporal succession in nature, including response to climate change. We compared temperature-related demography in closely related heat-tolerant and heat-sensitive Brachionus rotifer species. We found significant differences in heat response, with the heat-sensitive species adopting a strategy of long survival and low population growth, while the heat-tolerant followed the opposite strategy. In both species, we examined the genetic basis of physiological variation by comparing gene expression across increasing temperatures. Comparative transcriptomic analyses identified shared and opposing responses to heat. Interestingly, expression of heat shock proteins (hsps) was strikingly different in the two species and mirrored differences in population growth rates, showing that hsp genes are likely a key component of a species' adaptation to different temperatures. Temperature induction caused opposing patterns of expression in further functional categories including energy, carbohydrate and lipid metabolism, and in genes related to ribosomal proteins. In the heat-sensitive species, elevated temperatures caused up-regulation of genes related to meiosis induction and post-translational histone modifications. This work demonstrates the sweeping reorganizations of biological functions that accompany temperature adaptation in these two species and reveals potential molecular mechanisms that might be activated for adaptation to global warming.}, language = {en} } @article{ParaskevopoulouTiedemannWeithoff2018, author = {Paraskevopoulou, Sofia and Tiedemann, Ralph and Weithoff, Guntram}, title = {Differential response to heat stress among evolutionary lineages of an aquatic invertebrate species complex}, series = {Biology letters}, volume = {14}, journal = {Biology letters}, number = {11}, publisher = {Royal Society}, address = {London}, issn = {1744-9561}, doi = {10.1098/rsbl.2018.0498}, pages = {5}, year = {2018}, abstract = {Under global warming scenarios, rising temperatures can constitute heat stress to which species may respond differentially. Within a described species, knowledge on cryptic diversity is of further relevance, as different lineages/cryptic species may respond differentially to environmental change. The Brachionus calyciflorus species complex (Rotifera), which was recently described using integrative taxonomy, is an essential component of aquatic ecosystems. Here, we tested the hypothesis that these (formerly cryptic) species differ in their heat tolerance. We assigned 47 clones with nuclear ITS1 (nuITS1) and mitochondrial COI (mtCOI) markers to evolutionary lineages, now named B. calyciflorus sensu stricto (s.s.) and B. fernandoi. We selected 15 representative clones and assessed their heat tolerance as a bi-dimensional phenotypic trait affected by both the intensity and duration of heat stress. We found two distinct groups, with B. calyciflorus s.s. clones having higher heat tolerance than the novel species B. fernandoi. This apparent temperature specialization among former cryptic species underscores the necessity of a sound species delimitation and assignment, when organismal responses to environmental changes are investigated.}, language = {en} } @misc{ParrySchlaegelTiedemannetal.2022, author = {Parry, Victor and Schl{\"a}gel, Ulrike E. and Tiedemann, Ralph and Weithoff, Guntram}, title = {Behavioural Responses of Defended and Undefended Prey to Their Predator}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1302}, issn = {1866-8372}, doi = {10.25932/publishup-57759}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-577594}, pages = {14}, year = {2022}, abstract = {Predation is a strong species interaction causing severe harm or death to prey. Thus, prey species have evolved various defence strategies to minimize predation risk, which may be immediate (e.g., a change in behaviour) or transgenerational (morphological defence structures). We studied the behaviour of two strains of a rotiferan prey (Brachionus calyciflorus) that differ in their ability to develop morphological defences in response to their predator Asplanchna brightwellii. Using video analysis, we tested: (a) if two strains differ in their response to predator presence and predator cues when both are undefended; (b) whether defended individuals respond to live predators or their cues; and (c) if the morphological defence (large spines) per se has an effect on the swimming behaviour. We found a clear increase in swimming speed for both undefended strains in predator presence. However, the defended specimens responded neither to the predator presence nor to their cues, showing that they behave indifferently to their predator when they are defended. We did not detect an effect of the spines on the swimming behaviour. Our study demonstrates a complex plastic behaviour of the prey, not only in the presence of their predator, but also with respect to their defence status.}, language = {en} } @article{ParrySchlaegelTiedemannetal.2022, author = {Parry, Victor and Schl{\"a}gel, Ulrike E. and Tiedemann, Ralph and Weithoff, Guntram}, title = {Behavioural Responses of Defended and Undefended Prey to Their Predator}, series = {Biology}, volume = {11}, journal = {Biology}, number = {8}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2079-7737}, doi = {10.3390/biology11081217}, pages = {14}, year = {2022}, abstract = {Predation is a strong species interaction causing severe harm or death to prey. Thus, prey species have evolved various defence strategies to minimize predation risk, which may be immediate (e.g., a change in behaviour) or transgenerational (morphological defence structures). We studied the behaviour of two strains of a rotiferan prey (Brachionus calyciflorus) that differ in their ability to develop morphological defences in response to their predator Asplanchna brightwellii. Using video analysis, we tested: (a) if two strains differ in their response to predator presence and predator cues when both are undefended; (b) whether defended individuals respond to live predators or their cues; and (c) if the morphological defence (large spines) per se has an effect on the swimming behaviour. We found a clear increase in swimming speed for both undefended strains in predator presence. However, the defended specimens responded neither to the predator presence nor to their cues, showing that they behave indifferently to their predator when they are defended. We did not detect an effect of the spines on the swimming behaviour. Our study demonstrates a complex plastic behaviour of the prey, not only in the presence of their predator, but also with respect to their defence status.}, language = {en} } @article{ParrySchlaegelTiedemannetal.2022, author = {Parry, Victor and Schl{\"a}gel, Ulrike E. and Tiedemann, Ralph and Weithoff, Guntram}, title = {Behavioural responses of defended and undefended prey to their predator}, series = {Biology : open access journal}, volume = {11}, journal = {Biology : open access journal}, number = {8}, publisher = {MDPI}, address = {Basel}, issn = {2079-7737}, doi = {10.3390/biology11081217}, pages = {14}, year = {2022}, abstract = {Many animals that have to cope with predation have evolved mechanisms to reduce their predation risk. One of these mechanisms is change in morphology, for example, the development of spines. These spines are induced, when mothers receive chemical signals of a predator (kairomones) and their daughters are then equipped with defensive spines. We studied the behaviour of a prey and its predator when the prey is either defended or undefended. We used common aquatic micro-invertebrates, the rotifers Brachionus calyciflorus (prey) and Asplanchna brightwellii (predator) as experimental animals. We found that undefended prey increased its swimming speed in the presence of the predator. The striking result was that the defended prey did not respond to the predator's presence. This suggests that defended prey has a different response behaviour to a predator than undefended conspecifics. Our study provides further insights into complex zooplankton predator-prey interactions. Predation is a strong species interaction causing severe harm or death to prey. Thus, prey species have evolved various defence strategies to minimize predation risk, which may be immediate (e.g., a change in behaviour) or transgenerational (morphological defence structures). We studied the behaviour of two strains of a rotiferan prey (Brachionus calyciflorus) that differ in their ability to develop morphological defences in response to their predator Asplanchna brightwellii. Using video analysis, we tested: (a) if two strains differ in their response to predator presence and predator cues when both are undefended; (b) whether defended individuals respond to live predators or their cues; and (c) if the morphological defence (large spines) per se has an effect on the swimming behaviour. We found a clear increase in swimming speed for both undefended strains in predator presence. However, the defended specimens responded neither to the predator presence nor to their cues, showing that they behave indifferently to their predator when they are defended. We did not detect an effect of the spines on the swimming behaviour. Our study demonstrates a complex plastic behaviour of the prey, not only in the presence of their predator, but also with respect to their defence status.}, language = {en} } @article{PaulKirschbaumMamonekeneetal.2016, author = {Paul, Christiane and Kirschbaum, Frank and Mamonekene, Victor and Tiedemann, Ralph}, title = {Evidence for Non-neutral Evolution in a Sodium Channel Gene in African Weakly Electric Fish (Campylomormyrus, Mormyridae)}, series = {Journal of molecular evolution}, volume = {83}, journal = {Journal of molecular evolution}, publisher = {Springer}, address = {New York}, issn = {0022-2844}, doi = {10.1007/s00239-016-9754-8}, pages = {61 -- 77}, year = {2016}, abstract = {Voltage-gated sodium channels, Nav1, play a crucial role in the generation and propagation of action potentials and substantially contribute to the shape of their rising phase. The electric organ discharge (EOD) of African weakly electric fish (Mormyroidea) is the sum of action potentials fired from all electrocytes of the electric organ at the same time and hence voltage-gated sodium channels are one factor—together with the electrocyte's morphology and innervation pattern—that determines the properties of these EODs. Due to the fish-specific genome duplication, teleost fish possess eight copies of sodium channel genes (SCN), which encode for Nav1 channels. In mormyroids, SCN4aa is solely expressed in the electrocytes of the adult electric organ. In this study, we compared entire SCN4aa sequences of six species of the genus Campylomormyrus and identified nonsynonymous substitutions among them. SCN4aa in Campylomormyrus exhibits a much higher evolutionary rate compared to its paralog SCN4ab, whose expression is not restricted to the electric organ. We also found evidence for strong positive selection on the SCN4aa gene within Mormyridae and along the lineage ancestral to the Mormyridae. We have identified sites at which all nonelectric teleosts are monomorphic in their amino acid, but mormyrids have different amino acids. Our findings confirm the crucial role of SCN4aa in EOD evolution among mormyrid weakly electric fish. The inferred positive selection within Mormyridae makes this gene a prime candidate for further investigation of the divergent evolution of pulse-type EODs among closely related species.}, language = {en} } @article{PaulMamonekeneVateretal.2015, author = {Paul, Christiane and Mamonekene, Victor and Vater, Marianne and Feulner, Philine G. D. and Engelmann, Jacob and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Comparative histology of the adult electric organ among four species of the genus Campylomormyrus (Teleostei: Mormyridae)}, series = {Journal of comparative physiology : A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {201}, journal = {Journal of comparative physiology : A, Neuroethology, sensory, neural, and behavioral physiology}, number = {4}, publisher = {Springer}, address = {New York}, issn = {0340-7594}, doi = {10.1007/s00359-015-0995-6}, pages = {357 -- 374}, year = {2015}, abstract = {The electric organ (EO) of weakly electric mormyrids consists of flat, disk-shaped electrocytes with distinct anterior and posterior faces. There are multiple species-characteristic patterns in the geometry of the electrocytes and their innervation. To further correlate electric organ discharge (EOD) with EO anatomy, we examined four species of the mormyrid genus Campylomormyrus possessing clearly distinct EODs. In C. compressirostris, C. numenius, and C. tshokwe, all of which display biphasic EODs, the posterior face of the electrocytes forms evaginations merging to a stalk system receiving the innervation. In C. tamandua that emits a triphasic EOD, the small stalks of the electrocyte penetrate the electrocyte anteriorly before merging on the anterior side to receive the innervation. Additional differences in electrocyte anatomy among the former three species with the same EO geometry could be associated with further characteristics of their EODs. Furthermore, in C. numenius, ontogenetic changes in EO anatomy correlate with profound changes in the EOD. In the juvenile the anterior face of the electrocyte is smooth, whereas in the adult it exhibits pronounced surface foldings. This anatomical difference, together with disparities in the degree of stalk furcation, probably contributes to the about 12 times longer EOD in the adult.}, language = {en} } @article{PavesiDeMatthaeisTiedemannetal.2011, author = {Pavesi, Laura and De Matthaeis, Elvira and Tiedemann, Ralph and Ketmaier, Valerio}, title = {Temporal population genetics and COI phylogeography of the sandhopper macarorchestia remyi (Amphipoda: Talitridae)}, series = {Zoological studies}, volume = {50}, journal = {Zoological studies}, number = {2}, publisher = {Institute of Zoology, Academia Sinica}, address = {Taipei}, issn = {1021-5506}, pages = {220 -- 229}, year = {2011}, abstract = {Laura Pavesi, Elvira De Matthaeis, Ralph Tiedemann, and Valerio Ketmaier (2011) Temporal population genetics and COI phylogeography of the sandhopper Macarorchestia remyi (Amphipoda: Talitridae). Zoological Studies 50(2): 220-229. In this study we assessed levels of genetic divergence and variability in 208 individuals of the supralittoral sandhopper Macarorchestia remyi, a species strictly associated with rotted wood stranded on sand beaches, by analyzing sequence polymorphisms in a fragment of the mitochondrial DNA (mtDNA) gene coding cytochrome oxidase subunit I (COI). The geographical distribution and ecology of the species are poorly known. The study includes 1 Tyrrhenian and 2 Adriatic populations sampled along the Italian peninsula plus a single individual found on Corfu Is. (Greece). The Tyrrhenian population was sampled monthly for 1 yr. Genetic data revealed a deep phylogeographic break between the Tyrrhenian and Adriatic populations with no shared haplotypes. The single individual collected on Corfu Is. carried the most common haplotype found in the Tyrrhenian population. A mismatch analysis could not reject the hypothesis of a sudden demographic expansion in almost all but 2 monthly samples. When compared to previous genetic data centered on a variety of Mediterranean talitrids, our results place M. remyi among those species with profound intraspecific divergence (sandhoppers) and dissimilar from beachfleas, which generally display little population genetic structuring.}, language = {en} } @article{PavesiDeidunDeMatthaeisetal.2012, author = {Pavesi, Laura and Deidun, Alan and De Matthaeis, Elvira and Tiedemann, Ralph and Ketmaier, Valerio}, title = {Mitochondrial DNA and microsatellites reveal significant divergence in the beachflea Orchestia montagui (Talitridae: Amphipoda)}, series = {Aquatic sciences : research across boundaries}, volume = {74}, journal = {Aquatic sciences : research across boundaries}, number = {3}, publisher = {Springer}, address = {Basel}, issn = {1015-1621}, doi = {10.1007/s00027-012-0250-y}, pages = {587 -- 596}, year = {2012}, abstract = {Talitrids are semiterrestrial crustacean amphipods inhabiting sandy and rocky beaches; they generally show limited active dispersal over long distances. In this study we assessed levels of population genetic structure and variability in the talitrid amphipod Orchestia montagui, a species strictly associated to stranded decaying heaps of the seagrass Posidonia oceanica. The study is based on six populations (153 individuals) and covers five basins of the Mediterranean Sea (Tyrrhenian, Ionian, Adriatic, Western and Eastern basins). Samples were screened for polymorphisms at a fragment of the mitochondrial DNA (mtDNA) coding for the cytochrome oxidase subunit I gene (COI; 571 base pairs) and at eight microsatellite loci. MtDNA revealed a relatively homogeneous haplogroup, which clustered together the populations from the Western, Tyrrhenian and Eastern basins, but not the populations from the Adriatic and Ionian ones; microsatellites detected two clusters, one including the Adriatic and Ionian populations, the second grouping all the others. We found a weak geographic pattern in the genetic structuring of the species, with a lack of isolation by distance at either class of markers. Results are discussed in terms of probability of passive dispersal over long distances through heaps of seagrass.}, language = {en} } @article{PavesiTiedemannDeMatthaeisetal.2013, author = {Pavesi, Laura and Tiedemann, Ralph and De Matthaeis, Elvira and Ketmaier, Valerio}, title = {Genetic connectivity between land and sea - the case of the beachflea Orchestia montagui (Crustacea, Amphipoda, Talitridae) in the Mediterranean Sea}, series = {Frontiers in zoology}, volume = {10}, journal = {Frontiers in zoology}, number = {4-5}, publisher = {BioMed Central}, address = {London}, issn = {1742-9994}, doi = {10.1186/1742-9994-10-21}, pages = {19}, year = {2013}, abstract = {Introduction: We examined patterns of genetic divergence in 26 Mediterranean populations of the semi-terrestrial beachflea Orchestia montagui using mitochondrial (cytochrome oxidase subunit I), microsatellite (eight loci) and allozymic data. The species typically forms large populations within heaps of dead seagrass leaves stranded on beaches at the waterfront. We adopted a hierarchical geographic sampling to unravel population structure in a species living at the sea-land transition and, hence, likely subjected to dramatically contrasting forces. Results: Mitochondrial DNA showed historical phylogeographic breaks among Adriatic, Ionian and the remaining basins (Tyrrhenian, Western and Eastern Mediterranean Sea) likely caused by the geological and climatic changes of the Pleistocene. Microsatellites (and to a lesser extent allozymes) detected a further subdivision between and within the Western Mediterranean and the Tyrrhenian Sea due to present-day processes. A pattern of isolation by distance was not detected in any of the analyzed data set. Conclusions: We conclude that the population structure of O. montagui is the result of the interplay of two contrasting forces that act on the species population genetic structure. On one hand, the species semi-terrestrial life style would tend to determine the onset of local differences. On the other hand, these differences are partially counter-balanced by passive movements of migrants via rafting on heaps of dead seagrass leaves across sites by sea surface currents. Approximate Bayesian Computations support dispersal at sea as prevalent over terrestrial regionalism.}, language = {en} } @misc{PavesiTiedemannDeMatthaeisetal.2013, author = {Pavesi, Laura and Tiedemann, Ralph and De Matthaeis, Elvira and Ketmaier, Valerio}, title = {Genetic connectivity between land and sea}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401110}, pages = {19}, year = {2013}, abstract = {Introduction: We examined patterns of genetic divergence in 26 Mediterranean populations of the semi-terrestrial beachflea Orchestia montagui using mitochondrial (cytochrome oxidase subunit I), microsatellite (eight loci) and allozymic data. The species typically forms large populations within heaps of dead seagrass leaves stranded on beaches at the waterfront. We adopted a hierarchical geographic sampling to unravel population structure in a species living at the sea-land transition and, hence, likely subjected to dramatically contrasting forces. Results: Mitochondrial DNA showed historical phylogeographic breaks among Adriatic, Ionian and the remaining basins (Tyrrhenian, Western and Eastern Mediterranean Sea) likely caused by the geological and climatic changes of the Pleistocene. Microsatellites (and to a lesser extent allozymes) detected a further subdivision between and within the Western Mediterranean and the Tyrrhenian Sea due to present-day processes. A pattern of isolation by distance was not detected in any of the analyzed data set. Conclusions: We conclude that the population structure of O. montagui is the result of the interplay of two contrasting forces that act on the species population genetic structure. On one hand, the species semi-terrestrial life style would tend to determine the onset of local differences. On the other hand, these differences are partially counter-balanced by passive movements of migrants via rafting on heaps of dead seagrass leaves across sites by sea surface currents. Approximate Bayesian Computations support dispersal at sea as prevalent over terrestrial regionalism.}, language = {en} } @article{PavesiTiedemannDeMatthaeisetal.2013, author = {Pavesi, Laura and Tiedemann, Ralph and DeMatthaeis, Elvira and Ketmaier, Valerio}, title = {Genetic connectivity between land and sea: the case of the beachflea Orchestia montagui (Crustacea, Amphipoda, Talitridae) in the Mediterranean Sea}, issn = {1742-9994}, year = {2013}, language = {en} } @misc{PlathHermannSchroederetal.2010, author = {Plath, Martin and Hermann, Bernd and Schr{\"o}der, Christine and Riesch, R{\"u}diger and Tobler, Michael and Garc{\´i}a de Le{\´o}n, Francisco J. and Schlupp, Ingo and Tiedemann, Ralph}, title = {Locally adapted fish populations maintain small-scale genetic differentiation despite perturbation by a catastrophic flood event}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48599}, year = {2010}, abstract = {Background: Local adaptation to divergent environmental conditions can promote population genetic differentiation even in the absence of geographic barriers and hence, lead to speciation. Perturbations by catastrophic events, however, can distort such parapatric ecological speciation processes. Here, we asked whether an exceptionally strong flood led to homogenization of gene pools among locally adapted populations of the Atlantic molly (Poecilia mexicana, Poeciliidae) in the Cueva del Azufre system in southern Mexico, where two strong environmental selection factors (darkness within caves and/or presence of toxic H2S in sulfidic springs) drive the diversification of P. mexicana. Nine nuclear microsatellites as well as heritable female life history traits (both as a proxy for quantitative genetics and for trait divergence) were used as markers to compare genetic differentiation, genetic diversity, and especially population mixing (immigration and emigration) before and after the flood. Results: Habitat type (i.e., non-sulfidic surface, sulfidic surface, or sulfidic cave), but not geographic distance was the major predictor of genetic differentiation. Before and after the flood, each habitat type harbored a genetically distinct population. Only a weak signal of individual dislocation among ecologically divergent habitat types was uncovered (with the exception of slightly increased dislocation from the Cueva del Azufre into the sulfidic creek, El Azufre). By contrast, several lines of evidence are indicative of increased flood-induced dislocation within the same habitat type, e.g., between different cave chambers of the Cueva del Azufre. Conclusions: The virtual absence of individual dislocation among ecologically different habitat types indicates strong natural selection against migrants. Thus, our current study exemplifies that ecological speciation in this and other systems, in which extreme environmental factors drive speciation, may be little affected by temporary perturbations, as adaptations to physico-chemical stressors may directly affect the survival probability in divergent habitat types.}, language = {en} } @article{PlathKromuszczynskiTiedemann2009, author = {Plath, Martin and Kromuszczynski, Katja and Tiedemann, Ralph}, title = {Audience effect alters male but not female mating preferences}, issn = {0340-5443}, doi = {10.1007/s00265-008-0672-7}, year = {2009}, abstract = {Males often face strong mating competition by neighboring males in their social environment. A recent study by Plath et al. (Anim Behav 75:21-29, 2008a) has demonstrated that the visual presence of a male competitor (i.e., an audience male) affects the expression of male mating preferences in a poeciliid fish (Poecilia mexicana) with a weaker expression of mating preferences when an audience male observed the focal male. This may be a tactic to reduce sperm competition, since surrounding males likely share intrinsic preferences for female traits or copy mate choice decisions. Here, we examined the hypothesis that a same-sex audience would affect female mate preferences less than male mating preferences. Our hypothesis was based on the assumptions that (1) competition for mates in a fashion that would be comparable in strength to sperm competition or overt male-male aggression is absent among Poecilia females, and (2) P. mexicana females typically form female-biased shoals, such that almost any female mate choice in nature occurs in front of a female audience. Poecilia females (P. mexicana, surface and cave form, and the closely related gynogenetic Poecilia formosa) were given a choice between a large and a small male, and the tests were repeated while a conspecific, a heterospecific, or no audience female (control) was presented. Females spent more time in the neutral zone and, thus, less time near the males during the second part of a trial when an audience was presented, but-consistent with predictions-females showed only slightly weaker expression of mate preferences during the second part of the tests. This decline was not specific to the treatment involving an audience and was significantly weaker than the effect seen in the male sex.}, language = {en} } @misc{PokornySharmaGoyaletal.2011, author = {Pokorny, Ina and Sharma, Reeta and Goyal, Surendra Prakash and Mishra, Sudanshu and Tiedemann, Ralph}, title = {MHC class I and MHC class II DRB gene variability in wild and captive Bengal tigers (Panthera tigris tigris) (vol 10, pg 667, 2010)}, series = {Immunogenetics}, volume = {63}, journal = {Immunogenetics}, number = {2}, publisher = {Springer}, address = {New York}, issn = {0093-7711}, doi = {10.1007/s00251-010-0496-2}, pages = {121 -- 121}, year = {2011}, language = {en} } @article{RavaoarimananaTiedemannMontagnonetal.2004, author = {Ravaoarimanana, I. B. and Tiedemann, Ralph and Montagnon, D. and Rumpler, Y.}, title = {Molecular and cytogenetic evidence for cryptic speciation within a rare endemic Malagasy lemur, the Northern Sportive Lemur (Lepilemur septentrionalis)}, issn = {1055-7903}, year = {2004}, abstract = {Evolutionary relationships of different populations of the threatened malagasy lemur Lepilemur septentrimialis were assessed by sequence analysis of mitochondrial DNA (D-loop region and partial Cyt b gene). One hundred and fifty nine samples were collected from five main different localities in the northern part of Madagascar. We applied the phylogenetic species concept based on fixed diagnostic differences to determine the status of different geographical populations. No nucleotide site diagnoses Ankarana from Andrafiamena or Analamera. However, numerous fixed differences separate Sahafary from all other populations. These results were corroborated by phylogenetic trees. As previous cytogenetic studies, our molecular data suggest that two cryptic species of Lepilemur occur in the extreme north of Madagascar. This speciation is probably caused by chromosomal rearrangements in at least one of the evolutionary lineages. Our study comprises another striking example of how molecular genetic assay can detect phylogenetic discontinuities that are not reflected in traditional morphologically based taxonomies. Our study indicates that the Sahafary population is a hitherto undescribed endangered endemic species which urgently needs conservation efforts. (C) 2003 Elsevier Inc. All rights reserved}, language = {en} } @article{ReckendorfLudesWehrmeisterWohlseinetal.2018, author = {Reckendorf, Anja and Ludes-Wehrmeister, Eva and Wohlsein, Peter and Tiedemann, Ralph and Siebert, U. and Lehnert, Kristina}, title = {First record of Halocercus sp (Pseudaliidae) lungworm infections in two stranded neonatal orcas (Orcinus orca)}, series = {Parasitology}, volume = {145}, journal = {Parasitology}, number = {12}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {0031-1820}, doi = {10.1017/S0031182018000586}, pages = {1553 -- 1557}, year = {2018}, abstract = {Orca (Orcinus orca) strandings are rare and post-mortem examinations on fresh individuals are scarce. Thus, little is known about their parasitological fauna, prevalence of infections, associated pathology and the impact on their health. During post-mortem examinations of two male neonatal orcas stranded in Germany and Norway, lungworm infections were found within the bronchi of both individuals. The nematodes were identified as Halocercus sp. (Pseudaliidae), which have been described in the respiratory tract of multiple odontocete species, but not yet in orcas. The life cycle and transmission pathways of some pseudaliid nematodes are incompletely understood. Lungworm infections in neonatal cetaceans are an unusual finding and thus seem to be an indicator for direct mother-to-calf transmission (transplacental or transmammary) of Halocercus sp. nematodes in orcas.}, language = {en} } @misc{RomeroMujalliJeltschTiedemann2018, author = {Romero-Mujalli, Daniel and Jeltsch, Florian and Tiedemann, Ralph}, title = {Individual-based modeling of eco-evolutionary dynamics}, series = {Regional environmental change}, volume = {19}, journal = {Regional environmental change}, number = {1}, publisher = {Springer}, address = {Heidelberg}, issn = {1436-3798}, doi = {10.1007/s10113-018-1406-7}, pages = {1 -- 12}, year = {2018}, abstract = {A challenge for eco-evolutionary research is to better understand the effect of climate and landscape changes on species and their distribution. Populations of species can respond to changes in their environment through local genetic adaptation or plasticity, dispersal, or local extinction. The individual-based modeling (IBM) approach has been repeatedly applied to assess organismic responses to environmental changes. IBMs simulate emerging adaptive behaviors from the basic entities upon which both ecological and evolutionary mechanisms act. The objective of this review is to summarize the state of the art of eco-evolutionary IBMs and to explore to what degree they already address the key responses of organisms to environmental change. In this, we identify promising approaches and potential knowledge gaps in the implementation of eco-evolutionary mechanisms to motivate future research. Using mainly the ISI Web of Science, we reveal that most of the progress in eco-evolutionary IBMs in the last decades was achieved for genetic adaptation to novel local environmental conditions. There is, however, not a single eco-evolutionary IBM addressing the three potential adaptive responses simultaneously. Additionally, IBMs implementing adaptive phenotypic plasticity are rare. Most commonly, plasticity was implemented as random noise or reaction norms. Our review further identifies a current lack of models where plasticity is an evolving trait. Future eco-evolutionary models should consider dispersal and plasticity as evolving traits with their associated costs and benefits. Such an integrated approach could help to identify conditions promoting population persistence depending on the life history strategy of organisms and the environment they experience.}, language = {en} } @article{RomeroMujalliJeltschTiedemann2019, author = {Romero-Mujalli, Daniel and Jeltsch, Florian and Tiedemann, Ralph}, title = {Elevated mutation rates are unlikely to evolve in sexual species, not even under rapid environmental change}, series = {BMC Evolutionary Biology}, volume = {19}, journal = {BMC Evolutionary Biology}, publisher = {BioMed Central}, address = {London}, issn = {1471-2148}, doi = {10.1186/s12862-019-1494-0}, pages = {9}, year = {2019}, abstract = {Background Organisms are expected to respond to changing environmental conditions through local adaptation, range shift or local extinction. The process of local adaptation can occur by genetic changes or phenotypic plasticity, and becomes especially relevant when dispersal abilities or possibilities are somehow constrained. For genetic changes to occur, mutations are the ultimate source of variation and the mutation rate in terms of a mutator locus can be subject to evolutionary change. Recent findings suggest that the evolution of the mutation rate in a sexual species can advance invasion speed and promote adaptation to novel environmental conditions. Following this idea, this work uses an individual-based model approach to investigate if the mutation rate can also evolve in a sexual species experiencing different conditions of directional climate change, under different scenarios of colored stochastic environmental noise, probability of recombination and of beneficial mutations. The color of the noise mimicked investigating the evolutionary dynamics of the mutation rate in different habitats. Results The results suggest that the mutation rate in a sexual species experiencing directional climate change scenarios can evolve and reach relatively high values mainly under conditions of complete linkage of the mutator locus and the adaptation locus. In contrast, when they are unlinked, the mutation rate can slightly increase only under scenarios where at least 50\% of arising mutations are beneficial and the rate of environmental change is relatively fast. This result is robust under different scenarios of stochastic environmental noise, which supports the observation of no systematic variation in the mutation rate among organisms experiencing different habitats. Conclusions Given that 50\% beneficial mutations may be an unrealistic assumption, and that recombination is ubiquitous in sexual species, the evolution of an elevated mutation rate in a sexual species experiencing directional climate change might be rather unlikely. Furthermore, when the percentage of beneficial mutations and the population size are small, sexual species (especially multicellular ones) producing few offspring may be expected to react to changing environments not by adaptive genetic change, but mainly through plasticity. Without the ability for a plastic response, such species may become - at least locally - extinct.}, language = {en} } @misc{RomeroMujalliJeltschTiedemann2019, author = {Romero-Mujalli, Daniel and Jeltsch, Florian and Tiedemann, Ralph}, title = {Elevated mutation rates are unlikely to evolve in sexual species, not even under rapid environmental change}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {776}, issn = {1866-8372}, doi = {10.25932/publishup-43905}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439058}, pages = {11}, year = {2019}, abstract = {Background Organisms are expected to respond to changing environmental conditions through local adaptation, range shift or local extinction. The process of local adaptation can occur by genetic changes or phenotypic plasticity, and becomes especially relevant when dispersal abilities or possibilities are somehow constrained. For genetic changes to occur, mutations are the ultimate source of variation and the mutation rate in terms of a mutator locus can be subject to evolutionary change. Recent findings suggest that the evolution of the mutation rate in a sexual species can advance invasion speed and promote adaptation to novel environmental conditions. Following this idea, this work uses an individual-based model approach to investigate if the mutation rate can also evolve in a sexual species experiencing different conditions of directional climate change, under different scenarios of colored stochastic environmental noise, probability of recombination and of beneficial mutations. The color of the noise mimicked investigating the evolutionary dynamics of the mutation rate in different habitats. Results The results suggest that the mutation rate in a sexual species experiencing directional climate change scenarios can evolve and reach relatively high values mainly under conditions of complete linkage of the mutator locus and the adaptation locus. In contrast, when they are unlinked, the mutation rate can slightly increase only under scenarios where at least 50\% of arising mutations are beneficial and the rate of environmental change is relatively fast. This result is robust under different scenarios of stochastic environmental noise, which supports the observation of no systematic variation in the mutation rate among organisms experiencing different habitats. Conclusions Given that 50\% beneficial mutations may be an unrealistic assumption, and that recombination is ubiquitous in sexual species, the evolution of an elevated mutation rate in a sexual species experiencing directional climate change might be rather unlikely. Furthermore, when the percentage of beneficial mutations and the population size are small, sexual species (especially multicellular ones) producing few offspring may be expected to react to changing environments not by adaptive genetic change, but mainly through plasticity. Without the ability for a plastic response, such species may become - at least locally - extinct.}, language = {en} } @article{RomeroMujalliRochowKahletal.2021, author = {Romero-Mujalli, Daniel and Rochow, Markus and Kahl, Sandra M. and Paraskevopoulou, Sofia and Folkertsma, Remco and Jeltsch, Florian and Tiedemann, Ralph}, title = {Adaptive and nonadaptive plasticity in changing environments: Implications for sexual species with different life history strategies}, series = {Ecology and Evolution}, volume = {11}, journal = {Ecology and Evolution}, number = {11}, publisher = {John Wiley \& Sons, Inc.}, address = {New Jersey}, issn = {2045-7758}, pages = {17}, year = {2021}, abstract = {Populations adapt to novel environmental conditions by genetic changes or phenotypic plasticity. Plastic responses are generally faster and can buffer fitness losses under variable conditions. Plasticity is typically modeled as random noise and linear reaction norms that assume simple one-to- one genotype-phenotype maps and no limits to the phenotypic response. Most studies on plasticity have focused on its effect on population viability. However, it is not clear, whether the advantage of plasticity depends solely on environmental fluctuations or also on the genetic and demographic properties (life histories) of populations. Here we present an individual-based model and study the relative importance of adaptive and nonadaptive plasticity for populations of sexual species with different life histories experiencing directional stochastic climate change. Environmental fluctuations were simulated using differentially autocorrelated climatic stochasticity or noise color, and scenarios of directiona climate change. Nonadaptive plasticity was simulated as a random environmental effect on trait development, while adaptive plasticity as a linear, saturating, or sinusoidal reaction norm. The last two imposed limits to the plastic response and emphasized flexible interactions of the genotype with the environment. Interestingly, this assumption led to (a) smaller phenotypic than genotypic variance in the population (many-to- one genotype-phenotype map) and the coexistence of polymorphisms, and (b) the maintenance of higher genetic variation—compared to linear reaction norms and genetic determinism—even when the population was exposed to a constant environment for several generations. Limits to plasticity led to genetic accommodation, when costs were negligible, and to the appearance of cryptic variation when limits were exceeded. We found that adaptive plasticity promoted population persistence under red environmental noise and was particularly important for life histories with low fecundity. Populations produing more offspring could cope with environmental fluctuations solely by genetic changes or random plasticity, unless environmental change was too fast.}, language = {en} } @misc{RomeroMujalliRochowKahletal.2021, author = {Romero-Mujalli, Daniel and Rochow, Markus and Kahl, Sandra M. and Paraskevopoulou, Sofia and Folkertsma, Remco and Jeltsch, Florian and Tiedemann, Ralph}, title = {Adaptive and nonadaptive plasticity in changing environments: Implications for sexual species with different life history strategies}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1170}, issn = {1866-8372}, doi = {10.25932/publishup-52320}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-523201}, pages = {19}, year = {2021}, abstract = {Populations adapt to novel environmental conditions by genetic changes or phenotypic plasticity. Plastic responses are generally faster and can buffer fitness losses under variable conditions. Plasticity is typically modeled as random noise and linear reaction norms that assume simple one-to- one genotype-phenotype maps and no limits to the phenotypic response. Most studies on plasticity have focused on its effect on population viability. However, it is not clear, whether the advantage of plasticity depends solely on environmental fluctuations or also on the genetic and demographic properties (life histories) of populations. Here we present an individual-based model and study the relative importance of adaptive and nonadaptive plasticity for populations of sexual species with different life histories experiencing directional stochastic climate change. Environmental fluctuations were simulated using differentially autocorrelated climatic stochasticity or noise color, and scenarios of directiona climate change. Nonadaptive plasticity was simulated as a random environmental effect on trait development, while adaptive plasticity as a linear, saturating, or sinusoidal reaction norm. The last two imposed limits to the plastic response and emphasized flexible interactions of the genotype with the environment. Interestingly, this assumption led to (a) smaller phenotypic than genotypic variance in the population (many-to- one genotype-phenotype map) and the coexistence of polymorphisms, and (b) the maintenance of higher genetic variation—compared to linear reaction norms and genetic determinism—even when the population was exposed to a constant environment for several generations. Limits to plasticity led to genetic accommodation, when costs were negligible, and to the appearance of cryptic variation when limits were exceeded. We found that adaptive plasticity promoted population persistence under red environmental noise and was particularly important for life histories with low fecundity. Populations produing more offspring could cope with environmental fluctuations solely by genetic changes or random plasticity, unless environmental change was too fast.}, language = {en} } @article{SammlerBleidornTiedemann2011, author = {Sammler, Svenja and Bleidorn, Christoph and Tiedemann, Ralph}, title = {Full mitochondrial genome sequences of two endemic Philippine hornbill species (Aves: Bucerotidae) provide evidence for pervasive mitochondrial DNA recombination}, series = {BMC genomics}, volume = {12}, journal = {BMC genomics}, number = {2}, publisher = {BioMed Central}, address = {London}, issn = {1471-2164}, doi = {10.1186/1471-2164-12-35}, pages = {10}, year = {2011}, abstract = {Background: Although nowaday it is broadly accepted that mitochondrial DNA (mtDNA) may undergo recombination, the frequency of such recombination remains controversial. Its estimation is not straightforward, as recombination under homoplasmy (i.e., among identical mt genomes) is likely to be overlooked. In species with tandem duplications of large mtDNA fragments the detection of recombination can be facilitated, as it can lead to gene conversion among duplicates. Although the mechanisms for concerted evolution in mtDNA are not fully understood yet, recombination rates have been estimated from "one per speciation event" down to 850 years or even "during every replication cycle". Results: Here we present the first complete mt genome of the avian family Bucerotidae, i.e., that of two Philippine hornbills, Aceros waldeni and Penelopides panini. The mt genomes are characterized by a tandemly duplicated region encompassing part of cytochrome b, 3 tRNAs, NADH6, and the control region. The duplicated fragments are identical to each other except for a short section in domain I and for the length of repeat motifs in domain III of the control region. Due to the heteroplasmy with regard to the number of these repeat motifs, there is some size variation in both genomes; with around 21,657 bp (A. waldeni) and 22,737 bp (P. panini), they significantly exceed the hitherto longest known avian mt genomes, that of the albatrosses. We discovered concerted evolution between the duplicated fragments within individuals. The existence of differences between individuals in coding genes as well as in the control region, which are maintained between duplicates, indicates that recombination apparently occurs frequently, i. e., in every generation. Conclusions: The homogenised duplicates are interspersed by a short fragment which shows no sign of recombination. We hypothesize that this region corresponds to the so-called Replication Fork Barrier (RFB), which has been described from the chicken mitochondrial genome. As this RFB is supposed to halt replication, it offers a potential mechanistic explanation for frequent recombination in mitochondrial genomes.}, language = {en} } @misc{SammlerBleidornTiedemann2017, author = {Sammler, Svenja and Bleidorn, Christoph and Tiedemann, Ralph}, title = {Full mitochondrial genome sequences of two endemic Philippine hornbill species (Aves: Bucerotidae) provide evidence for pervasive mitochondrial DNA recombination}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400889}, pages = {10}, year = {2017}, abstract = {Background: Although nowaday it is broadly accepted that mitochondrial DNA (mtDNA) may undergo recombination, the frequency of such recombination remains controversial. Its estimation is not straightforward, as recombination under homoplasmy (i.e., among identical mt genomes) is likely to be overlooked. In species with tandem duplications of large mtDNA fragments the detection of recombination can be facilitated, as it can lead to gene conversion among duplicates. Although the mechanisms for concerted evolution in mtDNA are not fully understood yet, recombination rates have been estimated from "one per speciation event" down to 850 years or even "during every replication cycle". Results: Here we present the first complete mt genome of the avian family Bucerotidae, i.e., that of two Philippine hornbills, Aceros waldeni and Penelopides panini. The mt genomes are characterized by a tandemly duplicated region encompassing part of cytochrome b, 3 tRNAs, NADH6, and the control region. The duplicated fragments are identical to each other except for a short section in domain I and for the length of repeat motifs in domain III of the control region. Due to the heteroplasmy with regard to the number of these repeat motifs, there is some size variation in both genomes; with around 21,657 bp (A. waldeni) and 22,737 bp (P. panini), they significantly exceed the hitherto longest known avian mt genomes, that of the albatrosses. We discovered concerted evolution between the duplicated fragments within individuals. The existence of differences between individuals in coding genes as well as in the control region, which are maintained between duplicates, indicates that recombination apparently occurs frequently, i. e., in every generation. Conclusions: The homogenised duplicates are interspersed by a short fragment which shows no sign of recombination. We hypothesize that this region corresponds to the so-called Replication Fork Barrier (RFB), which has been described from the chicken mitochondrial genome. As this RFB is supposed to halt replication, it offers a potential mechanistic explanation for frequent recombination in mitochondrial genomes.}, language = {en} } @article{SammlerHavensteinTiedemann2012, author = {Sammler, Svenja and Havenstein, Katja and Tiedemann, Ralph}, title = {Fourteen new microsatellite markers for the Visayan tarictic hornbill (Penelopides panini) and their cross-species applicability among other endangered Philippine hornbills}, series = {Conservation genetics resources}, volume = {4}, journal = {Conservation genetics resources}, number = {2}, publisher = {Springer}, address = {Dordrecht}, issn = {1877-7252}, doi = {10.1007/s12686-011-9567-4}, pages = {435 -- 438}, year = {2012}, abstract = {Fourteen microsatellite markers were isolated and characterized for the endangered Visayan tarictic hornbill (Penelopides panini, Aves: Bucerotidae). In an analysis of 76 individuals, the number of alleles per locus varied from one to 12. Expected and observed heterozygosity ranged from 0.00 to 0.87 and from 0.00 to 0.89, respectively. All primers also amplify microsatellite loci in Luzon tarictic hornbill (Penelopides manillae), Mindanao tarictic hornbill (Penelopides affinis), the critically endangered Walden's hornbill (Aceros waldeni) and the near-threatened writhed hornbill (Aceros leucocephalus). Two loci which are monomorphic in P. panini were found polymorphic in at least one of the other species. These 14 new microsatellite markers specifically developed for two genera of Philippine hornbills, in combination with those already available for the hornbill genera Buceros and Bucorvus, comprise a reasonable number of loci to genetically analyse wild and captive populations of these and probably other related, often endangered hornbills.}, language = {en} } @phdthesis{SammlerKetmaierHavensteinetal.2012, author = {Sammler, Svenja and Ketmaier, Valerio and Havenstein, Katja and Krause, Ulrike and Curio, Eberhard and Tiedemann, Ralph}, title = {Mitochondrial control region I and microsatellite analyses of endangered Philippine hornbill species (Aves; Bucerotidae) detect gene flow between island populations and genetic diversity loss}, doi = {10.1186/1471-2148-12-203}, year = {2012}, language = {en} } @article{SammlerKetmaierHavensteinetal.2012, author = {Sammler, Svenja and Ketmaier, Valerio and Havenstein, Katja and Krause, Ulrike and Curio, Eberhard and Tiedemann, Ralph}, title = {Mitochondrial control region I and microsatellite analyses of endangered Philippine hornbill species (Aves; Bucerotidae) detect gene flow between island populations and genetic diversity loss}, series = {BMC evolutionary biology}, volume = {12}, journal = {BMC evolutionary biology}, number = {25}, publisher = {BioMed Central}, address = {London}, issn = {1471-2148}, doi = {10.1186/1471-2148-12-203}, pages = {14}, year = {2012}, abstract = {Background: The Visayan Tarictic Hornbill (Penelopides panini) and the Walden's Hornbill (Aceros waldeni) are two threatened hornbill species endemic to the western islands of the Visayas that constitute - between Luzon and Mindanao - the central island group of the Philippine archipelago. In order to evaluate their genetic diversity and to support efforts towards their conservation, we analyzed genetic variation in similar to 600 base pairs (bp) of the mitochondrial control region I and at 12-19 nuclear microsatellite loci. The sampling covered extant populations, still occurring only on two islands (P. panini: Panay and Negros, A. waldeni: only Panay), and it was augmented with museum specimens of extinct populations from neighboring islands. For comparison, their less endangered (= more abundant) sister taxa, the Luzon Tarictic Hornbill (P. manillae) from the Luzon and Polillo Islands and the Writhed Hornbill (A. leucocephalus) from Mindanao Island, were also included in the study. We reconstructed the population history of the two Penelopides species and assessed the genetic population structure of the remaining wild populations in all four species. Results: Mitochondrial and nuclear data concordantly show a clear genetic separation according to the island of origin in both Penelopides species, but also unravel sporadic over-water movements between islands. We found evidence that deforestation in the last century influenced these migratory events. Both classes of markers and the comparison to museum specimens reveal a genetic diversity loss in both Visayan hornbill species, P. panini and A. waldeni, as compared to their more abundant relatives. This might have been caused by local extinction of genetically differentiated populations together with the dramatic decline in the abundance of the extant populations. Conclusions: We demonstrated a loss in genetic diversity of P. panini and A. waldeni as compared to their sister taxa P. manillae and A. leucocephalus. Because of the low potential for gene flow and population exchange across islands, saving of the remaining birds of almost extinct local populations - be it in the wild or in captivity - is particularly important to preserve the species' genetic potential.}, language = {en} }