TY - JOUR A1 - De Cahsan, Binia A1 - Westbury, Michael V. A1 - Drews, Hauke A1 - Tiedemann, Ralph T1 - The complete mitochondrial genome of a European fire-bellied toad (Bombina bombina) from Germany JF - Mitochondrial DNA Part B N2 - 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. KW - Bombina bombina KW - Fire-bellied toad KW - mitogenome KW - conservation genetics KW - population delimitation Y1 - 2019 U6 - https://doi.org/10.1080/23802359.2018.1547143 SN - 2380-2359 VL - 4 IS - 1 SP - 498 EP - 500 PB - Taylor & Francis Group CY - London ER - TY - GEN A1 - De Cahsan, Binia A1 - Westbury, Michael V. A1 - Drews, Hauke A1 - Tiedemann, Ralph T1 - The complete mitochondrial genome of a European fire-bellied toad (Bombina bombina) from Germany T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 532 KW - Bombina bombina KW - Fire-bellied toad KW - mitogenome KW - conservation genetics KW - population delimitation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-423222 SN - 1866-8372 IS - 532 ER - TY - JOUR A1 - Barnett, Ross A1 - Westbury, Michael V. A1 - Sandoval-Velasco, Marcela A1 - Vieira, Filipe Garrett A1 - Jeon, Sungwon A1 - Zazula, Grant A1 - Martin, Michael D. A1 - Ho, Simon Y. W. A1 - Mather, Niklas A1 - Gopalakrishnan, Shyam A1 - Ramos-Madrigal, Jazmin A1 - de Manuel, Marc A1 - Zepeda-Mendoza, M. Lisandra A1 - Antunes, Agostinho A1 - Baez, Aldo Carmona A1 - De Cahsan, Binia A1 - Larson, Greger A1 - O'Brien, Stephen J. A1 - Eizirik, Eduardo A1 - Johnson, Warren E. A1 - Koepfli, Klaus-Peter A1 - Wilting, Andreas A1 - Fickel, Jörns A1 - Dalen, Love A1 - Lorenzen, Eline D. A1 - Marques-Bonet, Tomas A1 - Hansen, Anders J. A1 - Zhang, Guojie A1 - Bhak, Jong A1 - Yamaguchi, Nobuyuki A1 - Gilbert, M. Thomas P. T1 - Genomic adaptations and evolutionary history of the extinct scimitar-toothed cat BT - Homotherium latidens JF - Current biology N2 - Homotherium was a genus of large-bodied scimitar-toothed cats, morphologically distinct from any extant felid species, that went extinct at the end of the Pleistocene [1-4]. They possessed large, saber-form serrated canine teeth, powerful forelimbs, a sloping back, and an enlarged optic bulb, all of which were key characteristics for predation on Pleistocene megafauna [5]. Previous mitochondrial DNA phylogenies suggested that it was a highly divergent sister lineage to all extant cat species [6-8]. However, mitochondrial phylogenies can be misled by hybridization [9], incomplete lineage sorting (ILS), or sex-biased dispersal patterns [10], which might be especially relevant for Homotherium since widespread mito-nuclear discrepancies have been uncovered in modern cats [10]. To examine the evolutionary history of Homotherium, we generated a -7x nuclear genome and a similar to 38x exome from H. latidens using shotgun and target-capture sequencing approaches. Phylogenetic analyses reveal Homotherium as highly divergent (similar to 22.5 Ma) from living cat species, with no detectable signs of gene flow. Comparative genomic analyses found signatures of positive selection in several genes, including those involved in vision, cognitive function, and energy consumption, putatively consistent with diurnal activity, well-developed social behavior, and cursorial hunting [5]. Finally, we uncover relatively high levels of genetic diversity, suggesting that Homotherium may have been more abundant than the limited fossil record suggests [3, 4, 11-14]. Our findings complement and extend previous inferences from both the fossil record and initial molecular studies, enhancing our understanding of the evolution and ecology of this remarkable lineage. Y1 - 2020 U6 - https://doi.org/10.1016/j.cub.2020.09.051 SN - 0960-9822 SN - 1879-0445 VL - 30 IS - 24 PB - Cell Press CY - Cambridge ER - TY - JOUR A1 - De Cahsan, Binia A1 - Nagel, Rebecca A1 - Schedina, Ina-Maria A1 - King, James J. A1 - Bianco, Pier G. A1 - Tiedemann, Ralph A1 - Ketmaier, Valerio T1 - Phylogeography of the European brook lamprey (Lampetra planeri) and the European river lamprey (Lampetra fluviatilis) species pair based on mitochondrial data JF - Journal of fish biology N2 - 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. KW - European lamprey KW - Lampetra KW - paired species KW - phylogeography KW - population KW - structure Y1 - 2020 U6 - https://doi.org/10.1111/jfb.14279 SN - 0022-1112 SN - 1095-8649 VL - 96 IS - 4 SP - 905 EP - 912 PB - Wiley-Blackwell CY - Oxford [u.a.] ER - TY - JOUR A1 - Cahsan, Binia De A1 - Westbury, Michael V. A1 - Paraskevopoulou, Sofia A1 - Drews, Hauke A1 - Ott, Moritz A1 - Gollmann, Günter A1 - Tiedemann, Ralph T1 - Genomic consequences of human-mediated translocations in margin populations of an endangered amphibian JF - Evolutionary Applications N2 - 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. KW - adaptive introgression KW - admixture KW - Bombina bombina KW - genetic rescue KW - mitogenomes KW - transcriptomics Y1 - 2020 SN - 1752-4563 VL - 14 IS - 6 PB - John Wiley & Sons, Inc. CY - New Jersey ER - TY - GEN A1 - Cahsan, Binia De A1 - Westbury, Michael V. A1 - Paraskevopoulou, Sofia A1 - Drews, Hauke A1 - Ott, Moritz A1 - Gollmann, Günter A1 - Tiedemann, Ralph T1 - Genomic consequences of human-mediated translocations in margin populations of an endangered amphibian T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1168 KW - adaptive introgression KW - admixture KW - Bombina bombina KW - genetic rescue KW - mitogenomes KW - transcriptomics Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-523140 SN - 1866-8372 IS - 6 ER - TY - GEN A1 - Cahsan, Binia De A1 - Kiemel, Katrin A1 - Westbury, Michael V. A1 - Lauritsen, Maike A1 - Autenrieth, Marijke A1 - Gollmann, Günter A1 - Schweiger, Silke A1 - Stenberg, Marika A1 - Nyström, Per A1 - Drews, Hauke A1 - Tiedemann, Ralph T1 - Southern introgression increases adaptive immune gene variability in northern range margin populations of Fire-bellied toad T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - 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 (Skåne), 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1177 KW - Bombina bombina KW - heat shock protein KW - introgression KW - major histocompatibility complex KW - scaled mass index Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-523883 SN - 1866-8372 IS - 14 ER - TY - JOUR A1 - Cahsan, Binia De A1 - Kiemel, Katrin A1 - Westbury, Michael V. A1 - Lauritsen, Maike A1 - Autenrieth, Marijke A1 - Gollmann, Günter A1 - Schweiger, Silke A1 - Stenberg, Marika A1 - Nyström, Per A1 - Drews, Hauke A1 - Tiedemann, Ralph T1 - Southern introgression increases adaptive immune gene variability in northern range margin populations of Fire-bellied toad JF - Ecology and Evolution N2 - 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 (Skåne), 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. KW - Bombina bombina KW - heat shock protein KW - introgression KW - major histocompatibility complex KW - scaled mass index Y1 - 2021 SN - 2045-7758 VL - 11 IS - 14 PB - John Wiley & Sons, Inc. CY - New Jersey ER - TY - JOUR A1 - Kiemel, Katrin A1 - De Cahsan, Binia A1 - Paraskevopoulou, Sofia A1 - Weithoff, Guntram A1 - Tiedemann, Ralph T1 - 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) JF - Mitochondrial DNA. Part B-Resources N2 - 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). KW - Mitogenome KW - cryptic species KW - Brachionus calyciflorus s KW - Brachionus KW - fernandoi KW - monogonont rotifer Y1 - 2022 U6 - https://doi.org/10.1080/23802359.2022.2060765 SN - 2380-2359 VL - 7 IS - 4 SP - 646 EP - 648 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - THES A1 - De Cahsan, Binia T1 - Introgressive hybridization in northern range margin populations of the European fire-bellied toad (Bombina bombina) N2 - The European fire-bellied toad (Bombina bombina) is regarded as one of the most threatened species of amphibians in central Europe and is particularly affected by environmental perturbations. During the last decades population numbers in Germany have declined drastically due to pollution, eutrophication and habitat fragmentation. Illegal translocations resulted in an introgression from southern genotypes (probably Austrian) into three local Bombina populations (Northern Germany and Southern Sweden) belonging to the northern lineage of the species. Interestingly, these populations show high frequencies of allochthonous (non-local) alleles at multiple loci and outperform the autochthonous populations in terms of their body condition. Over a time period of ten years, I could show that the Southern lineage haplo- and genotypes are still present in the North and that frequencies of introgressed haplotypes in allochthonous populations did not increase over time. However, the introgression itself expanded towards adjacent populations while the overall haplotype diversity has decreased. In contrast, southern lineage genotypes for two candidate genes under selection, the (immunity) MHC class II gene, as well as the (temperature) stress response HSP70 kDa gene, either do not occur at all or only at low frequencies in northern populations. Furthermore, these alleles do not seem to follow the introgression pattern, as they are also present in non-introgressed populations. This thesis tested two possible outcomes of introgressive hybridization in Northern B. bombina populations: (1) local populations (autochthonous) of Bombina bombina are highly adapted to their environments so that introgression of alien genes causes outbreeding depression or (2) local populations of Bombina bombina potentially lack adaptive variation so that introgression of alien genes causes genetic rescue and promotes adaptive change. I found that this unintentional experiment, as a result of illegal translocations imitating introgression of alien genes coming from a southern population (potentially adapted to warmer climate) into a northern lineage (potentially adapted to local pathogens), has increased the genetic diversity and improved fitness in introgressed northern populations, without disrupting local adaptation in the threatened amphibian species B. bombina, favouring the genetic rescue hypothesis. These results and conclusions represent relevant information for future conservation plans, including supportive breeding programmes for fire-bellied toads in Northern Germany and Southern Sweden. N2 - Die Europäische Rotbauchunke (B. bombina) gilt als eine der meist bedrohten Amphibienarten Zentraleuropas und ist besonders betroffen von Umweltveränderungen und damit einhergehenden ökologischen Störungen. In den letzten Jahrzehnten sind die Populationsbestände in Deutschland durch Umweltverschmutzung, Überdüngung sowie Habitatfragmentierung drastisch zurückgegangen. Illegale Translokationen haben zu einer Introgression von südlichen Genotypen (mutmaßlich aus Österreich stammend) in drei lokalen Bombina-Populationen (Norddeutschland und Südschweden), die zur nördlichen Artabstammungslinie gehören, geführt. Interessanterweise zeigen diese Populationen allochthone (nicht lokale) Allele an mehreren Loci in hoher Frequenz und übertreffen die autochthonen Populationen in ihrer körperlichen Fitness. Diese Arbeit konnte dokumentieren, dass nach einem Zeitraum von zehn Jahren die Haplo- und Genotypen der südlichen Linie noch immer im Norden vorhanden sind und sich die Frequenz in allochthonen Populationen seitdem nicht erhöht hat. Trotzalledem konnte gezeigt werden, dass eine weitere Ausbreitung der Introgression in nahegelegene Populationen stattfand, während sich die Gesamthaplotypendiversität jedoch verringert hat. Im Gegensatz dazu, kommen südliche Allele bei Genen, welche unter Selektionsdruck stehen, beispielsweise die Immunitäts-MHCKlasse-II-Gene und das in die Temperatur- und Stressantwort involvierte HSP70-kDa-Gen, entweder gar nicht oder nur in geringer Frequenz in den nördlichen Populationen vor. Zusätzlich dazu scheinen diese Allele nicht dem Introgressionsmuster zu folgen, da sie auch in nicht-introgressierten Populationen vorzufinden sind. Diese Arbeit diente der Untersuchung zweier möglicher Folgen von introgressiver Hybridisierung in nördlichen B. bombina Populationen: (1) lokale B. bombina Populationen (autochthon) sind hochgradig angepasst an ihre nördliche Umwelt, so dass Introgression von Fremdallelen Auszuchtdepression (outbreeding depression) verursacht oder (2) lokale B. bombina Populationen (autochthon) haben womöglich geringe genetische Anpassungsvariation, so dass Introgression von Fremdgenen eine genetische Rettung (genetic rescue) darstellt und so adaptive Veränderungen fördert. Dieses ungeplante Experiment, das Introgression von Fremdgenen einer südlichen Abstammungslinie (potentiell angepasst an wärmeres Klima) in die nördliche Linie (potentiell angepasst an lokale Pathogene) als Folge von illegaler Aussetzung aufzeigt, führte zu einer Steigerung der genetischen Diversität und Fitness in von Introgression betroffenen, nördlichen Populationen ohne dabei die lokale Anpassung dieser bedrohten Amphibienart zu zerstören. Dies entspräche der Genetic-Rescue-Hypothese. Die in dieser Arbeit gewonnenen Ergebnisse und Schlussfolgerungen sind wichtige und relevante Informationen für zukünftige Naturschutzmaßnahmen und deren Managementstrategien, einschließlich unterstützende Zuchtprogramme für Rotbauchunken-Populationen in Norddeutschland und Südschweden. KW - Genetic rescue KW - Bombina bombina KW - Amphibians KW - conservation genetics KW - Introgression KW - Genetische Rettung KW - Bombina bombina KW - Amphibien KW - Naturschutzgenetik KW - Introgression Y1 - CY - Potsdam ER -