@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{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}
}
@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{WronskiWacherHammondetal.2010,
  author    = {Wronski, Torsten and Wacher, Timothy and Hammond, Robert L. and Winney, Bruce and Hundertmark, Kris J. and Blacket, Mark J. and Mohammed, Osama B. and Flores, Benito and Omer, Sawsan A. and Macasero, William and Plath, Martin and Tiedemann, Ralph and Bleidorn, Christoph},
  title     = {Two reciprocally monophyletic mtDNA lineages elucidate the taxonomic status of Mountain gazelles (Gazella gazella)},
  issn      = {1477-2000},
  doi       = {10.1080/14772001003613192},
  year      = {2010},
  abstract  = {Mountain gazelles (Gazella gazella) rank among the most critically endangered mammals on the Arabian Peninsula. Past conservation efforts have been plagued by confusion about the phylogenetic relationship among various 'phenotypically discernable' populations, and even the question of species boundaries was far from being certain. This lack of knowledge has had a direct impact on conservation measures, especially ex situ breeding programmes, hampering the assignment of captive stocks to potential conservation units. Here, we provide a phylogenetic framework, based on the analysis of mtDNA sequences (360 bp cytochrome b and 213 bp Control Region) of 126 individuals collected from the wild throughout the Arabian Peninsula and from captive stocks. Our analyses revealed two reciprocally monophyletic genetic lineages within the presumed species Gazella gazella: one 'northern clade' on the Golan Heights (Israel/Syrian border) and one genetically diverse larger clade from the rest of the Arabian Peninsula including the Arava Valley (Negev, Israel). Applying the Strict Phylogenetic Species Concept (sensu Mishler \& Theriot, 2000) allows assigning species status to these two major clades.},
  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{SchedinaGrothSchluppetal.2018,
  author    = {Schedina, Ina Maria and Groth, Detlef and Schlupp, Ingo and Tiedemann, Ralph},
  title     = {The gonadal transcriptome of the unisexual Amazon molly Poecilia formosa in comparison to its sexual ancestors, Poecilia mexicana and Poecilia latipinna},
  series = {BMC Genomics},
  volume    = {19},
  journal   = {BMC Genomics},
  number    = {12},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2164},
  doi       = {10.1186/s12864-017-4382-2},
  pages     = {1 -- 18},
  year      = {2018},
  abstract  = {Background The unisexual Amazon molly (Poecilia formosa) originated from a hybridization between two sexual species, the sailfin molly (Poecilia latipinna) and the Atlantic molly (Poecilia mexicana). The Amazon molly reproduces clonally via sperm-dependent parthenogenesis (gynogenesis), in which the sperm of closely related species triggers embryogenesis of the apomictic oocytes, but typically does not contribute genetic material to the next generation. We compare for the first time the gonadal transcriptome of the Amazon molly to those of both ancestral species, P. mexicana and P. latipinna. Results We sequenced the gonadal transcriptomes of the P. formosa and its parental species P. mexicana and P. latipinna using Illumina RNA-sequencing techniques (paired-end, 100 bp). De novo assembly of about 50 million raw read pairs for each species was performed using Trinity, yielding 106,922 transcripts for P. formosa, 115,175 for P. latipinna, and 133,025 for P. mexicana after eliminating contaminations. On the basis of sequence similarity comparisons to other teleost species and the UniProt databases, functional annotation, and differential expression analysis, we demonstrate the similarity of the transcriptomes among the three species. More than 40\% of the transcripts for each species were functionally annotated and about 70\% were assigned to orthologous genes of a closely related species. Differential expression analysis between the sexual and unisexual species uncovered 2035 up-regulated and 564 down-regulated genes in P. formosa. This was exemplary validated for six genes by qRT-PCR. Conclusions We identified more than 130 genes related to meiosis and reproduction within the apomictically reproducing P. formosa. Overall expression of these genes seems to be down-regulated in the P. formosa transcriptome compared to both ancestral species (i.e., 106 genes down-regulated, 29 up-regulated). A further 35 meiosis and reproduction related genes were not found in the P. formosa transcriptome, but were only expressed in the sexual species. Our data support the hypothesis of general down-regulation of meiosis-related genes in the apomictic Amazon molly. Furthermore, the obtained dataset and identified gene catalog will serve as a resource for future research on the molecular mechanisms behind the reproductive mode of this unisexual species.},
  language  = {en}
}
@article{VernesiPecchioliTiedemannetal.2002,
  author    = {Vernesi, C. and Pecchioli, E. and Tiedemann, Ralph and Randi, E. and Bertorelle, G.},
  title     = {The genetic structure of natural and reintroduced roe deer (Capreolus capreolus) populations in the Alps and central Italy, with reference to the mitochondrial DNA phylogeography of Europe},
  issn      = {0962-1083},
  year      = {2002},
  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{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}
}
@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}
}