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Sebastian Steinfartz - One of the best experts on this subject based on the ideXlab platform.
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strong correlation between cross amplification success and Genetic Distance across all members of true salamanders amphibia salamandridae revealed by salamandra salamandra specific microsatellite loci
Molecular Ecology Resources, 2010Co-Authors: Ralf Hendrix, Susanne J Hauswaldt, Michael Veith, Sebastian SteinfartzAbstract:The unpredictable and low cross-amplification success of microsatellite loci tested for congeneric amphibian species has mainly been explained by the size and complexity of amphibian genomes, but also by taxonomy that is inconsistent with phyloGenetic relationships among taxa. Here, we tested whether the cross-amplification success of nine new and 11 published microsatellite loci cloned for an amphibian source species, the fire salamander (Salamandra salamandra), correlated with the Genetic Distance across all members of True Salamanders (genera Chioglossa, Lyciasalamandra, Mertensiella and Salamandra that form a monophyletic clade within the family of Salamandridae) serving as target species. Cross-amplification success varied strongly among the species and showed a highly significant negative relationship with Genetic Distance and amplification success. Even though lineages of S. salamandra and Lyciasalamndra have separated more than 30 Ma, aw ithin genus amplif ication success rate of 65% was achieved for species of Lyciasalamandra thus demonstrating that an efficient cross-species amplification of microsatellite loci in amphibians is feasible even across large evolutionary Distances. A decrease in genome size, on the other hand, paralleled also a decrease in amplified loci and therefore contradicted previous results and expectations that amplification success should increase with a decrease in genome size. However, in line with other studies, our comprehensive dataset clearly shows that cross-amplification success of microsatellite loci is well explained by phyloGenetic divergence between species. As taxonomic classifications on the species and genus level do not necessarily mirror phyloGenetic divergence between species, the pure belonging of species to the same taxonomic units (i.e. species or genus) might be less useful to predict cross-amplification success of microsatellite loci between such species.
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habitat adaptation rather than Genetic Distance correlates with female preference in fire salamanders salamandra salamandra
Frontiers in Zoology, 2009Co-Authors: Barbara A Caspers, Claudia Junge, Markus Weitere, Sebastian SteinfartzAbstract:Background Although some mechanisms of habitat adaptation of conspecific populations have been recently elucidated, the evolution of female preference has rarely been addressed as a force driving habitat adaptation in natural settings. Habitat adaptation of fire salamanders (Salamandra salamandra), as found in Middle Europe (Germany), can be framed in an explicit phylogeographic framework that allows for the evolution of habitat adaptation between distinct populations to be traced. Typically, females of S. salamandra only deposit their larvae in small permanent streams. However, some populations of the western post-glacial recolonization lineage use small temporary ponds as larval habitats. Pond larvae display several habitat-specific adaptations that are absent in stream-adapted larvae. We conducted mate preference tests with females from three distinct German populations in order to determine the influence of habitat adaptation versus neutral Genetic Distance on female mate choice. Two populations that we tested belong to the western post-glacial recolonization group, but are adapted to either stream or pond habitats. The third population is adapted to streams but represents the eastern recolonization lineage.
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habitat adaptation rather than Genetic Distance correlates with female preference in fire salamanders salamandra salamandra
Frontiers in Zoology, 2009Co-Authors: Barbara A Caspers, Claudia Junge, Markus Weitere, Sebastian SteinfartzAbstract:Background: Although some mechanisms of habitat adaptation of conspecific populations have been recently elucidated, the evolution of female preference has rarely been addressed as a force driving habitat adaptation in natural settings. Habitat adaptation of fire salamanders (Salamandra salamandra), as found in Middle Europe (Germany), can be framed in an explicit phylogeographic framework that allows for the evolution of habitat adaptation between distinct populations to be traced. Typically, females of S. salamandra only deposit their larvae in small permanent streams. However, some populations of the western post-glacial recolonization lineage use small temporary ponds as larval habitats. Pond larvae display several habitat-specific adaptations that are absent in stream-adapted larvae. We conducted mate preference tests with females from three distinct German populations in order to determine the influence of habitat adaptation versus neutral Genetic Distance on female mate choice. Two populations that we tested belong to the western post-glacial recolonization group, but are adapted to either stream or pond habitats. The third population is adapted to streams but represents the eastern recolonization lineage. Results: Despite large Genetic Distances with FST values around 0.5, the stream-adapted females preferred males from the same habitat type regardless of Genetic Distance. Conversely, pondadapted females did not prefer males from their own population when compared to streamadapted individuals of either lineage. Conclusion: A comparative analysis of our data showed that habitat adaptation rather than neutral Genetic Distance correlates with female preference in these salamanders, and that habitatdependent female preference of a specific pond-reproducing population may have been lost during adaptation to the novel environmental conditions of ponds.
Ole Seehausen - One of the best experts on this subject based on the ideXlab platform.
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phenotypic novelty in experimental hybrids is predicted by the Genetic Distance between species of cichlid fish
BMC Evolutionary Biology, 2009Co-Authors: Rike B Stelkens, Corinne Schmid, Oliver Selz, Ole SeehausenAbstract:Background Transgressive segregation describes the occurrence of novel phenotypes in hybrids with extreme trait values not observed in either parental species. A previously experimentally untested prediction is that the amount of transgression increases with the Genetic Distance between hybridizing species. This follows from QTL studies suggesting that transgression is most commonly due to complementary gene action or epistasis, which become more frequent at larger Genetic Distances. This is because the number of QTLs fixed for alleles with opposing signs in different species should increase with time since speciation provided that speciation is not driven by disruptive selection. We measured the amount of transgression occurring in hybrids of cichlid fish bred from species pairs with gradually increasing Genetic Distances and varying phenotypic similarity. Transgression in multi-trait shape phenotypes was quantified using landmark-based geometric morphometric methods.
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phenotypic novelty in experimental hybrids is predicted by the Genetic Distance between species of cichlid fish
BMC Evolutionary Biology, 2009Co-Authors: Rike B Stelkens, Corinne Schmid, Oliver Selz, Ole SeehausenAbstract:Transgressive segregation describes the occurrence of novel phenotypes in hybrids with extreme trait values not observed in either parental species. A previously experimentally untested prediction is that the amount of transgression increases with the Genetic Distance between hybridizing species. This follows from QTL studies suggesting that transgression is most commonly due to complementary gene action or epistasis, which become more frequent at larger Genetic Distances. This is because the number of QTLs fixed for alleles with opposing signs in different species should increase with time since speciation provided that speciation is not driven by disruptive selection. We measured the amount of transgression occurring in hybrids of cichlid fish bred from species pairs with gradually increasing Genetic Distances and varying phenotypic similarity. Transgression in multi-trait shape phenotypes was quantified using landmark-based geometric morphometric methods. We found that Genetic Distance explained 52% and 78% of the variation in transgression frequency in F1 and F2 hybrids, respectively. Confirming theoretical predictions, transgression when measured in F2 hybrids, increased linearly with Genetic Distance between hybridizing species. Phenotypic similarity of species on the other hand was not related to the amount of transgression. The commonness and ease with which novel phenotypes are produced in cichlid hybrids between unrelated species has important implications for the interaction of hybridization with adaptation and speciation. Hybridization may generate new genotypes with adaptive potential that did not reside as standing Genetic variation in either parental population, potentially enhancing a population's responsiveness to selection. Our results make it conceivable that hybridization contributed to the rapid rates of phenotypic evolution in the large and rapid adaptive radiations of haplochromine cichlids.
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Genetic Distance between species predicts novel trait expression in their hybrids
Evolution, 2009Co-Authors: Rike B Stelkens, Ole SeehausenAbstract:Interspecific hybridization can generate transgressive hybrid phenotypes with extreme trait values exceeding the combined range of the parental species. Such variation can enlarge the working surface for natural selection, and may facilitate the evolution of novel adaptations where ecological opportunity exists. The number of quantitative trait loci fixed for different alleles in different species should increase with time since speciation. If transgression is caused by complementary gene action or epistasis, hybrids between more distant species should be more likely to display transgressive phenotypes. To test this prediction we collected data on transgression frequency from the literature, estimated Genetic Distances between the hybridizing species from gene sequences, and calculated the relationship between the two using phyloGenetically controlled methods. We also tested if parental phenotypic divergence affected the occurrence of transgression. We found a highly significant positive correlation between transgression frequency and Genetic Distance in eudicot plants explaining 43% of the variance in transgression frequency. In total, 36% of the measured traits were transgressive. The predicted effect of time since speciation on transgressive segregation was unconfounded by the potentially conflicting effects of phenotypic differentiation between species. Our analysis demonstrates that the potential impact hybridization may have on phenotypic evolution is predictable from the Genetic Distance between species.
Rike B Stelkens - One of the best experts on this subject based on the ideXlab platform.
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phenotypic novelty in experimental hybrids is predicted by the Genetic Distance between species of cichlid fish
BMC Evolutionary Biology, 2009Co-Authors: Rike B Stelkens, Corinne Schmid, Oliver Selz, Ole SeehausenAbstract:Background Transgressive segregation describes the occurrence of novel phenotypes in hybrids with extreme trait values not observed in either parental species. A previously experimentally untested prediction is that the amount of transgression increases with the Genetic Distance between hybridizing species. This follows from QTL studies suggesting that transgression is most commonly due to complementary gene action or epistasis, which become more frequent at larger Genetic Distances. This is because the number of QTLs fixed for alleles with opposing signs in different species should increase with time since speciation provided that speciation is not driven by disruptive selection. We measured the amount of transgression occurring in hybrids of cichlid fish bred from species pairs with gradually increasing Genetic Distances and varying phenotypic similarity. Transgression in multi-trait shape phenotypes was quantified using landmark-based geometric morphometric methods.
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phenotypic novelty in experimental hybrids is predicted by the Genetic Distance between species of cichlid fish
BMC Evolutionary Biology, 2009Co-Authors: Rike B Stelkens, Corinne Schmid, Oliver Selz, Ole SeehausenAbstract:Transgressive segregation describes the occurrence of novel phenotypes in hybrids with extreme trait values not observed in either parental species. A previously experimentally untested prediction is that the amount of transgression increases with the Genetic Distance between hybridizing species. This follows from QTL studies suggesting that transgression is most commonly due to complementary gene action or epistasis, which become more frequent at larger Genetic Distances. This is because the number of QTLs fixed for alleles with opposing signs in different species should increase with time since speciation provided that speciation is not driven by disruptive selection. We measured the amount of transgression occurring in hybrids of cichlid fish bred from species pairs with gradually increasing Genetic Distances and varying phenotypic similarity. Transgression in multi-trait shape phenotypes was quantified using landmark-based geometric morphometric methods. We found that Genetic Distance explained 52% and 78% of the variation in transgression frequency in F1 and F2 hybrids, respectively. Confirming theoretical predictions, transgression when measured in F2 hybrids, increased linearly with Genetic Distance between hybridizing species. Phenotypic similarity of species on the other hand was not related to the amount of transgression. The commonness and ease with which novel phenotypes are produced in cichlid hybrids between unrelated species has important implications for the interaction of hybridization with adaptation and speciation. Hybridization may generate new genotypes with adaptive potential that did not reside as standing Genetic variation in either parental population, potentially enhancing a population's responsiveness to selection. Our results make it conceivable that hybridization contributed to the rapid rates of phenotypic evolution in the large and rapid adaptive radiations of haplochromine cichlids.
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Genetic Distance between species predicts novel trait expression in their hybrids
Evolution, 2009Co-Authors: Rike B Stelkens, Ole SeehausenAbstract:Interspecific hybridization can generate transgressive hybrid phenotypes with extreme trait values exceeding the combined range of the parental species. Such variation can enlarge the working surface for natural selection, and may facilitate the evolution of novel adaptations where ecological opportunity exists. The number of quantitative trait loci fixed for different alleles in different species should increase with time since speciation. If transgression is caused by complementary gene action or epistasis, hybrids between more distant species should be more likely to display transgressive phenotypes. To test this prediction we collected data on transgression frequency from the literature, estimated Genetic Distances between the hybridizing species from gene sequences, and calculated the relationship between the two using phyloGenetically controlled methods. We also tested if parental phenotypic divergence affected the occurrence of transgression. We found a highly significant positive correlation between transgression frequency and Genetic Distance in eudicot plants explaining 43% of the variance in transgression frequency. In total, 36% of the measured traits were transgressive. The predicted effect of time since speciation on transgressive segregation was unconfounded by the potentially conflicting effects of phenotypic differentiation between species. Our analysis demonstrates that the potential impact hybridization may have on phenotypic evolution is predictable from the Genetic Distance between species.
Samuel A Cushman - One of the best experts on this subject based on the ideXlab platform.
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a comparison of individual based Genetic Distance metrics for landscape Genetics
Molecular Ecology Resources, 2017Co-Authors: Andrew J Shirk, Erin L Landguth, Samuel A CushmanAbstract:A major aim of landscape Genetics is to understand how landscapes resist gene flow and thereby influence population Genetic structure. An empirical understanding of this process provides a wealth of information that can be used to guide conservation and management of species in fragmented landscapes, and also to predict how landscape change may affect population viability. Statistical approaches to infer the true model among competing alternatives are based on the strength of the relationship between pairwise Genetic Distances and landscape Distances among sampled individuals in a population. A variety of methods have been devised to quantify individual Genetic Distances, but no study has yet compared their relative performance when used for model selection in landscape Genetics. In this study, we used population Genetic simulations to assess the accuracy of 16 individual-based Genetic Distance metrics under varying sample sizes and degree of population Genetic structure. We found most metrics performed well when sample size and Genetic structure was high. However, it was much more challenging to infer the true model when sample size and Genetic structure was low. Under these conditions, we found Genetic Distance metrics based on principal components analysis were the most accurate (though several other metrics performed similarly), but only when they were derived from multiple principal component axes (the optimal number varied depending on the degree of population Genetic structure). Our results provide guidance for which Genetic Distance metrics maximize model selection accuracy and thereby better inform conservation and management decisions based upon landscape Genetic analysis. This article is protected by copyright. All rights reserved.
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a comparison of individual based Genetic Distance metrics for landscape Genetics
Molecular Ecology Resources, 2017Co-Authors: Andrew J Shirk, Erin L Landguth, Samuel A CushmanAbstract:A major aim of landscape Genetics is to understand how landscapes resist gene flow and thereby influence population Genetic structure. An empirical understanding of this process provides a wealth of information that can be used to guide conservation and management of species in fragmented landscapes and also to predict how landscape change may affect population viability. Statistical approaches to infer the true model among competing alternatives are based on the strength of the relationship between pairwise Genetic Distances and landscape Distances among sampled individuals in a population. A variety of methods have been devised to quantify individual Genetic Distances, but no study has yet compared their relative performance when used for model selection in landscape Genetics. In this study, we used population Genetic simulations to assess the accuracy of 16 individual-based Genetic Distance metrics under varying sample sizes and degree of population Genetic structure. We found most metrics performed well when sample size and Genetic structure was high. However, it was much more challenging to infer the true model when sample size and Genetic structure was low. Under these conditions, we found Genetic Distance metrics based on principal components analysis were the most accurate (although several other metrics performed similarly), but only when they were derived from multiple principal components axes (the optimal number varied depending on the degree of population Genetic structure). Our results provide guidance for which Genetic Distance metrics maximize model selection accuracy and thereby better inform conservation and management decisions based upon landscape Genetic analysis.
Andrew J Shirk - One of the best experts on this subject based on the ideXlab platform.
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a comparison of individual based Genetic Distance metrics for landscape Genetics
Molecular Ecology Resources, 2017Co-Authors: Andrew J Shirk, Erin L Landguth, Samuel A CushmanAbstract:A major aim of landscape Genetics is to understand how landscapes resist gene flow and thereby influence population Genetic structure. An empirical understanding of this process provides a wealth of information that can be used to guide conservation and management of species in fragmented landscapes, and also to predict how landscape change may affect population viability. Statistical approaches to infer the true model among competing alternatives are based on the strength of the relationship between pairwise Genetic Distances and landscape Distances among sampled individuals in a population. A variety of methods have been devised to quantify individual Genetic Distances, but no study has yet compared their relative performance when used for model selection in landscape Genetics. In this study, we used population Genetic simulations to assess the accuracy of 16 individual-based Genetic Distance metrics under varying sample sizes and degree of population Genetic structure. We found most metrics performed well when sample size and Genetic structure was high. However, it was much more challenging to infer the true model when sample size and Genetic structure was low. Under these conditions, we found Genetic Distance metrics based on principal components analysis were the most accurate (though several other metrics performed similarly), but only when they were derived from multiple principal component axes (the optimal number varied depending on the degree of population Genetic structure). Our results provide guidance for which Genetic Distance metrics maximize model selection accuracy and thereby better inform conservation and management decisions based upon landscape Genetic analysis. This article is protected by copyright. All rights reserved.
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a comparison of individual based Genetic Distance metrics for landscape Genetics
Molecular Ecology Resources, 2017Co-Authors: Andrew J Shirk, Erin L Landguth, Samuel A CushmanAbstract:A major aim of landscape Genetics is to understand how landscapes resist gene flow and thereby influence population Genetic structure. An empirical understanding of this process provides a wealth of information that can be used to guide conservation and management of species in fragmented landscapes and also to predict how landscape change may affect population viability. Statistical approaches to infer the true model among competing alternatives are based on the strength of the relationship between pairwise Genetic Distances and landscape Distances among sampled individuals in a population. A variety of methods have been devised to quantify individual Genetic Distances, but no study has yet compared their relative performance when used for model selection in landscape Genetics. In this study, we used population Genetic simulations to assess the accuracy of 16 individual-based Genetic Distance metrics under varying sample sizes and degree of population Genetic structure. We found most metrics performed well when sample size and Genetic structure was high. However, it was much more challenging to infer the true model when sample size and Genetic structure was low. Under these conditions, we found Genetic Distance metrics based on principal components analysis were the most accurate (although several other metrics performed similarly), but only when they were derived from multiple principal components axes (the optimal number varied depending on the degree of population Genetic structure). Our results provide guidance for which Genetic Distance metrics maximize model selection accuracy and thereby better inform conservation and management decisions based upon landscape Genetic analysis.