Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes
The concept of the species has traditionally been the principal unit for the classification of the diversity of life. Although the conceptual and legal relevance of the idea of species is profound and wide ranging it is also increasingly evident that the concept of species is a significant oversimpl...
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Language: | English |
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2016
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ftcdlib:qt3d88n0kr 2023-05-15T18:42:17+02:00 Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes Cahill, James Andrew 244 2016-01-01 application/pdf http://www.escholarship.org/uc/item/3d88n0kr en eng eScholarship, University of California http://www.escholarship.org/uc/item/3d88n0kr qt3d88n0kr Attribution-NonCommercial-NoDerivs (CC BY-NC-ND ): http://creativecommons.org/licenses/by-nc-nd/3.0/ CC-BY-NC-ND Cahill, James Andrew. (2016). Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes. UC Santa Cruz: Ecology and Evolutionary Biology. Retrieved from: http://www.escholarship.org/uc/item/3d88n0kr Genetics Evolution & development Bioinformatics Bears Evolution Genomics Hybridization dissertation 2016 ftcdlib 2017-01-13T23:50:08Z The concept of the species has traditionally been the principal unit for the classification of the diversity of life. Although the conceptual and legal relevance of the idea of species is profound and wide ranging it is also increasingly evident that the concept of species is a significant oversimplification of the complex processes at work in nature. The growing body of evidence from genomic data, and other sources, indicates that interspecific hybridization plays a much more substantial role in evolution than had previously been appreciated and that speciation, the formation of new species, is likely a more gradual process than had been appreciated. In my dissertation work, I have applied whole genome sequencing and ancient DNA based techniques to examine the evolutionary relationship of two closely related species, polar bears (Ursus maritimus) and brown bears (Ursus arctos), which occupy substantially different ecological niches. This work is presented in a series of three papers that have contributed to reshaping scientific understanding of the relatedness of polar bears and brown bears and suggest that climate changes can profoundly impact the frequency of hybridization between these two species. I have also contributed to method development – in a fourth paper my coauthors and I developed a novel application of existing analysis tools to estimate the end point of the speciation process, the time at which all gene flow has ceased, from genomic data. Finally, in collaboration with my co-first author Axel Barlow and colleagues, I have examined the evolutionary relationship between polar and brown bears and their closest extinct relatives, the cave bears, which has revealed previously undocumented admixture between cave bears and brown bears and provides insights into the extent of diversity within the paleo-species groups of cave bear. Doctoral or Postdoctoral Thesis Ursus arctos Ursus maritimus University of California: eScholarship |
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Open Polar |
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University of California: eScholarship |
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ftcdlib |
language |
English |
topic |
Genetics Evolution & development Bioinformatics Bears Evolution Genomics Hybridization |
spellingShingle |
Genetics Evolution & development Bioinformatics Bears Evolution Genomics Hybridization Cahill, James Andrew Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
topic_facet |
Genetics Evolution & development Bioinformatics Bears Evolution Genomics Hybridization |
description |
The concept of the species has traditionally been the principal unit for the classification of the diversity of life. Although the conceptual and legal relevance of the idea of species is profound and wide ranging it is also increasingly evident that the concept of species is a significant oversimplification of the complex processes at work in nature. The growing body of evidence from genomic data, and other sources, indicates that interspecific hybridization plays a much more substantial role in evolution than had previously been appreciated and that speciation, the formation of new species, is likely a more gradual process than had been appreciated. In my dissertation work, I have applied whole genome sequencing and ancient DNA based techniques to examine the evolutionary relationship of two closely related species, polar bears (Ursus maritimus) and brown bears (Ursus arctos), which occupy substantially different ecological niches. This work is presented in a series of three papers that have contributed to reshaping scientific understanding of the relatedness of polar bears and brown bears and suggest that climate changes can profoundly impact the frequency of hybridization between these two species. I have also contributed to method development – in a fourth paper my coauthors and I developed a novel application of existing analysis tools to estimate the end point of the speciation process, the time at which all gene flow has ceased, from genomic data. Finally, in collaboration with my co-first author Axel Barlow and colleagues, I have examined the evolutionary relationship between polar and brown bears and their closest extinct relatives, the cave bears, which has revealed previously undocumented admixture between cave bears and brown bears and provides insights into the extent of diversity within the paleo-species groups of cave bear. |
format |
Doctoral or Postdoctoral Thesis |
author |
Cahill, James Andrew |
author_facet |
Cahill, James Andrew |
author_sort |
Cahill, James Andrew |
title |
Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
title_short |
Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
title_full |
Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
title_fullStr |
Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
title_full_unstemmed |
Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes |
title_sort |
investigating the causes and consequences of admixture between polar bears and brown bears using ancient and modern genomes |
publisher |
eScholarship, University of California |
publishDate |
2016 |
url |
http://www.escholarship.org/uc/item/3d88n0kr |
op_coverage |
244 |
genre |
Ursus arctos Ursus maritimus |
genre_facet |
Ursus arctos Ursus maritimus |
op_source |
Cahill, James Andrew. (2016). Investigating the Causes and Consequences of Admixture between Polar Bears and Brown Bears using Ancient and Modern Genomes. UC Santa Cruz: Ecology and Evolutionary Biology. Retrieved from: http://www.escholarship.org/uc/item/3d88n0kr |
op_relation |
http://www.escholarship.org/uc/item/3d88n0kr qt3d88n0kr |
op_rights |
Attribution-NonCommercial-NoDerivs (CC BY-NC-ND ): http://creativecommons.org/licenses/by-nc-nd/3.0/ |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766231923975258112 |