Divergence, gene flow, and the speciation continuum in trans-Beringian birds
Thesis (M.S.) University of Alaska Fairbanks, 2017 Understanding the processes of divergence and speciation, particularly in the presence of gene flow, is key to understanding the generation of biodiversity. I investigated divergence and gene flow in nine lineages of birds with a trans-Beringian dis...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/7894 2023-05-15T15:43:59+02:00 Divergence, gene flow, and the speciation continuum in trans-Beringian birds McLaughlin, Jessica F. Winker, Kevin Takebayashi, Naoki Hundertmark, Chris 2017-08 http://hdl.handle.net/11122/7894 en_US eng http://hdl.handle.net/11122/7894 Department of Biology and Wildlife Birds Speciation Russia (Federation) Bering Sea Coast Alaska North Pacific Region Genetics Thesis ms 2017 ftunivalaska 2023-02-23T21:36:57Z Thesis (M.S.) University of Alaska Fairbanks, 2017 Understanding the processes of divergence and speciation, particularly in the presence of gene flow, is key to understanding the generation of biodiversity. I investigated divergence and gene flow in nine lineages of birds with a trans-Beringian distribution, including pairs of populations, subspecies, and species, using loci containing ultraconserved elements (UCEs). I found that although these lineages spanned conditions from panmixia to fully biologically isolated species, they were not smoothly distributed across this continuum, but formed two discontinuous groups: relatively shallow splits with gene flow between Asian and North American populations, no fixed SNPs, and lower divergence; and relatively deeply split lineages with multiple fixed SNPs, higher divergence, and relatively low rates of gene flow. All eight lineages in which two populations were distinguishable shared the same divergence model, one with gene flow without a prolonged period of isolation. This was despite the diversity of lineages included that might not have responded in the same ways to the glacial-interglacial cycles of connection and isolation in Beringia. Together, these results highlight the role of gene flow in influencing divergence in these Beringian lineages. Sample size is a critical aspect of study design in population genomics research, yet few empirical studies have examined the impacts of small sample sizes. Using split-migration models optimized with full datasets, I subsampled the datasets from Chapter 1 at sequentially smaller sample sizes from full datasets of 6 - 8 diploid individuals per population and then compared parameter estimates and their variances. Effective population size parameters (ν) tended to be underestimated at low sample sizes (fewer than 3 diploid individuals per population), migration (m) was fairly reliably estimated until under 2 individuals per population, and no trend of over- or underestimation was found in either time since divergence (T) ... Thesis Bering Sea Alaska Beringia University of Alaska: ScholarWorks@UA Bering Sea Fairbanks Pacific |
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Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
topic |
Birds Speciation Russia (Federation) Bering Sea Coast Alaska North Pacific Region Genetics |
spellingShingle |
Birds Speciation Russia (Federation) Bering Sea Coast Alaska North Pacific Region Genetics McLaughlin, Jessica F. Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
topic_facet |
Birds Speciation Russia (Federation) Bering Sea Coast Alaska North Pacific Region Genetics |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2017 Understanding the processes of divergence and speciation, particularly in the presence of gene flow, is key to understanding the generation of biodiversity. I investigated divergence and gene flow in nine lineages of birds with a trans-Beringian distribution, including pairs of populations, subspecies, and species, using loci containing ultraconserved elements (UCEs). I found that although these lineages spanned conditions from panmixia to fully biologically isolated species, they were not smoothly distributed across this continuum, but formed two discontinuous groups: relatively shallow splits with gene flow between Asian and North American populations, no fixed SNPs, and lower divergence; and relatively deeply split lineages with multiple fixed SNPs, higher divergence, and relatively low rates of gene flow. All eight lineages in which two populations were distinguishable shared the same divergence model, one with gene flow without a prolonged period of isolation. This was despite the diversity of lineages included that might not have responded in the same ways to the glacial-interglacial cycles of connection and isolation in Beringia. Together, these results highlight the role of gene flow in influencing divergence in these Beringian lineages. Sample size is a critical aspect of study design in population genomics research, yet few empirical studies have examined the impacts of small sample sizes. Using split-migration models optimized with full datasets, I subsampled the datasets from Chapter 1 at sequentially smaller sample sizes from full datasets of 6 - 8 diploid individuals per population and then compared parameter estimates and their variances. Effective population size parameters (ν) tended to be underestimated at low sample sizes (fewer than 3 diploid individuals per population), migration (m) was fairly reliably estimated until under 2 individuals per population, and no trend of over- or underestimation was found in either time since divergence (T) ... |
author2 |
Winker, Kevin Takebayashi, Naoki Hundertmark, Chris |
format |
Thesis |
author |
McLaughlin, Jessica F. |
author_facet |
McLaughlin, Jessica F. |
author_sort |
McLaughlin, Jessica F. |
title |
Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
title_short |
Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
title_full |
Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
title_fullStr |
Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
title_full_unstemmed |
Divergence, gene flow, and the speciation continuum in trans-Beringian birds |
title_sort |
divergence, gene flow, and the speciation continuum in trans-beringian birds |
publishDate |
2017 |
url |
http://hdl.handle.net/11122/7894 |
geographic |
Bering Sea Fairbanks Pacific |
geographic_facet |
Bering Sea Fairbanks Pacific |
genre |
Bering Sea Alaska Beringia |
genre_facet |
Bering Sea Alaska Beringia |
op_relation |
http://hdl.handle.net/11122/7894 Department of Biology and Wildlife |
_version_ |
1766378203166801920 |