Insights into bear evolution from a Pleistocene polar bear genome
© 2022 National Academy of Sciences. All rights reserved. cc-by-nc-nd The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods...
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fttexastechuniv:oai:ttu-ir.tdl.org:2346/92501 2023-05-15T14:18:10+02:00 Insights into bear evolution from a Pleistocene polar bear genome Lan, Tianying Leppala, Kalle Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojarvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis (TTU) Lindqvist, Charlotte 2022 application/pdf https://hdl.handle.net/2346/92501 https://doi.org/10.1073/pnas.2200016119 eng eng Lan, T., Leppala, K., Tomlin, C., Talbot, S.L., Sage, G.K., Farley, S.D., Shideler, R.T., Bachmann, L., Wiig, O., Albert, V.A., Salojarvi, J., Mailund, T., Drautz-Moses, D.I., Schuster, S.C., Herrera-Estrella, L., & Lindqvist, C. 2022. Insights into bear evolution from a Pleistocene polar bear genome. Proceedings of the National Academy of Sciences of the United States of America, 119(24). https://doi.org/10.1073/pnas.2200016119 https://doi.org/10.1073/pnas.2200016119 https://hdl.handle.net/2346/92501 bear evolution climate change comparative genomics hybridization Ursus Article 2022 fttexastechuniv https://doi.org/10.1073/pnas.2200016119 2023-04-08T22:06:52Z © 2022 National Academy of Sciences. All rights reserved. cc-by-nc-nd The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000- to 115,000-y-old polar bear from the Svalbard Archipelago using a 10× coverage genome sequence and 10 new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear's lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 y. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published work. These findings may have implications for our understanding of climate change impacts: Polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks but also been the recipient of generalist, boreal genetic variants from brown bears during critical phases of Northern Hemisphere glacial oscillations. Article in Journal/Newspaper Archipelago Arctic Climate change Svalbard Ursus arctos Ursus maritimus Alaska Texas Tech University: TTU DSpace Repository Arctic Svalbard Svalbard Archipelago Proceedings of the National Academy of Sciences 119 24 |
institution |
Open Polar |
collection |
Texas Tech University: TTU DSpace Repository |
op_collection_id |
fttexastechuniv |
language |
English |
topic |
bear evolution climate change comparative genomics hybridization Ursus |
spellingShingle |
bear evolution climate change comparative genomics hybridization Ursus Lan, Tianying Leppala, Kalle Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojarvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis (TTU) Lindqvist, Charlotte Insights into bear evolution from a Pleistocene polar bear genome |
topic_facet |
bear evolution climate change comparative genomics hybridization Ursus |
description |
© 2022 National Academy of Sciences. All rights reserved. cc-by-nc-nd The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000- to 115,000-y-old polar bear from the Svalbard Archipelago using a 10× coverage genome sequence and 10 new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear's lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 y. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published work. These findings may have implications for our understanding of climate change impacts: Polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks but also been the recipient of generalist, boreal genetic variants from brown bears during critical phases of Northern Hemisphere glacial oscillations. |
format |
Article in Journal/Newspaper |
author |
Lan, Tianying Leppala, Kalle Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojarvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis (TTU) Lindqvist, Charlotte |
author_facet |
Lan, Tianying Leppala, Kalle Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojarvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis (TTU) Lindqvist, Charlotte |
author_sort |
Lan, Tianying |
title |
Insights into bear evolution from a Pleistocene polar bear genome |
title_short |
Insights into bear evolution from a Pleistocene polar bear genome |
title_full |
Insights into bear evolution from a Pleistocene polar bear genome |
title_fullStr |
Insights into bear evolution from a Pleistocene polar bear genome |
title_full_unstemmed |
Insights into bear evolution from a Pleistocene polar bear genome |
title_sort |
insights into bear evolution from a pleistocene polar bear genome |
publishDate |
2022 |
url |
https://hdl.handle.net/2346/92501 https://doi.org/10.1073/pnas.2200016119 |
geographic |
Arctic Svalbard Svalbard Archipelago |
geographic_facet |
Arctic Svalbard Svalbard Archipelago |
genre |
Archipelago Arctic Climate change Svalbard Ursus arctos Ursus maritimus Alaska |
genre_facet |
Archipelago Arctic Climate change Svalbard Ursus arctos Ursus maritimus Alaska |
op_relation |
Lan, T., Leppala, K., Tomlin, C., Talbot, S.L., Sage, G.K., Farley, S.D., Shideler, R.T., Bachmann, L., Wiig, O., Albert, V.A., Salojarvi, J., Mailund, T., Drautz-Moses, D.I., Schuster, S.C., Herrera-Estrella, L., & Lindqvist, C. 2022. Insights into bear evolution from a Pleistocene polar bear genome. Proceedings of the National Academy of Sciences of the United States of America, 119(24). https://doi.org/10.1073/pnas.2200016119 https://doi.org/10.1073/pnas.2200016119 https://hdl.handle.net/2346/92501 |
op_doi |
https://doi.org/10.1073/pnas.2200016119 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
119 |
container_issue |
24 |
_version_ |
1766289864801648640 |