The genomic signatures of adaptive evolution in Populus
Understanding the genetic basis of adaptive evolution, and how natural selection has shaped patterns of polymorphism and divergence within and between species are enduring goals of evolutionary genetics. In this thesis, I used whole genome re-sequencing data to characterize the genomic signatures of...
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Umeå universitet, Institutionen för ekologi, miljö och geovetenskap
2016
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ftumeauniv:oai:DiVA.org:umu-120286 2023-10-09T21:50:18+02:00 The genomic signatures of adaptive evolution in Populus Wang, Jing 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120286 eng eng Umeå universitet, Institutionen för ekologi, miljö och geovetenskap Umeå : Umeå University orcid:0000-0002-3793-3264 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120286 urn:isbn:978-91-7601-463-9 info:eu-repo/semantics/openAccess Populus adaptive evolution natural selection genomic diversity and divergence recombination Next-generation sequencing local adaptation Ecology Ekologi Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2016 ftumeauniv 2023-09-22T13:48:56Z Understanding the genetic basis of adaptive evolution, and how natural selection has shaped patterns of polymorphism and divergence within and between species are enduring goals of evolutionary genetics. In this thesis, I used whole genome re-sequencing data to characterize the genomic signatures of natural selection along different evolutionary timescales in three Populus species: Populus tremula, P. tremuloides and P. trichocarpa. First, our study shows multiple lines of evidence suggesting that natural selection, due to both positive and purifying selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. Second, we characterize the evolution of genomic divergence patterns between two recently diverged aspen species: P. tremula and P. tremuloides. Our findings indicate that the two species diverged ~2.2-3.1 million years ago, coinciding with the severing of the Bering land bridge and the onset of dramatic climatic oscillations during the Pleistocene. We further explore different mechanisms that may explain the heterogeneity of genomic divergence, and find that variation in linked selection and recombination likely plays a key role in generating the heterogeneous genomic landscape of differentiation between the two aspen species. Third, we link whole-genome polymorphic data with local environmental variables and phenotypic variation in an adaptive trait to investigate the genomic basis of local adaptation in P. tremula along a latitudinal gradient across Sweden. We find that a majority of single nucleotide polymorphisms (SNPs) (>90%) identified as being involved in local adaptation are tightly clustered in a single genomic region on chromosome 10. The signatures of selection at this region are more consistent with soft rather than hard selective sweeps, where multiple adaptive ... Doctoral or Postdoctoral Thesis Bering Land Bridge Umeå University: Publications (DiVA) |
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Umeå University: Publications (DiVA) |
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ftumeauniv |
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English |
topic |
Populus adaptive evolution natural selection genomic diversity and divergence recombination Next-generation sequencing local adaptation Ecology Ekologi |
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Populus adaptive evolution natural selection genomic diversity and divergence recombination Next-generation sequencing local adaptation Ecology Ekologi Wang, Jing The genomic signatures of adaptive evolution in Populus |
topic_facet |
Populus adaptive evolution natural selection genomic diversity and divergence recombination Next-generation sequencing local adaptation Ecology Ekologi |
description |
Understanding the genetic basis of adaptive evolution, and how natural selection has shaped patterns of polymorphism and divergence within and between species are enduring goals of evolutionary genetics. In this thesis, I used whole genome re-sequencing data to characterize the genomic signatures of natural selection along different evolutionary timescales in three Populus species: Populus tremula, P. tremuloides and P. trichocarpa. First, our study shows multiple lines of evidence suggesting that natural selection, due to both positive and purifying selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. Second, we characterize the evolution of genomic divergence patterns between two recently diverged aspen species: P. tremula and P. tremuloides. Our findings indicate that the two species diverged ~2.2-3.1 million years ago, coinciding with the severing of the Bering land bridge and the onset of dramatic climatic oscillations during the Pleistocene. We further explore different mechanisms that may explain the heterogeneity of genomic divergence, and find that variation in linked selection and recombination likely plays a key role in generating the heterogeneous genomic landscape of differentiation between the two aspen species. Third, we link whole-genome polymorphic data with local environmental variables and phenotypic variation in an adaptive trait to investigate the genomic basis of local adaptation in P. tremula along a latitudinal gradient across Sweden. We find that a majority of single nucleotide polymorphisms (SNPs) (>90%) identified as being involved in local adaptation are tightly clustered in a single genomic region on chromosome 10. The signatures of selection at this region are more consistent with soft rather than hard selective sweeps, where multiple adaptive ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Wang, Jing |
author_facet |
Wang, Jing |
author_sort |
Wang, Jing |
title |
The genomic signatures of adaptive evolution in Populus |
title_short |
The genomic signatures of adaptive evolution in Populus |
title_full |
The genomic signatures of adaptive evolution in Populus |
title_fullStr |
The genomic signatures of adaptive evolution in Populus |
title_full_unstemmed |
The genomic signatures of adaptive evolution in Populus |
title_sort |
genomic signatures of adaptive evolution in populus |
publisher |
Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120286 |
genre |
Bering Land Bridge |
genre_facet |
Bering Land Bridge |
op_relation |
orcid:0000-0002-3793-3264 http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120286 urn:isbn:978-91-7601-463-9 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779313356388171776 |