Insights into bear evolution from a Pleistocene polar bear genome
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 studi...
Published in: | Proceedings of the National Academy of Sciences |
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Online Access: | http://hdl.handle.net/10138/348204 |
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/348204 2023-12-17T10:22:39+01:00 Insights into bear evolution from a Pleistocene polar bear genome Lan, Tianying Leppälä, Kalle Matias Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojärvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis Lindqvist, Charlotte Organismal and Evolutionary Biology Research Programme University of Helsinki 2022-09-20T07:31:03Z 11 application/pdf http://hdl.handle.net/10138/348204 eng eng https://doi.org/10.1073/pnas.2200016119 Proceedings of the National Academy of Sciences of the United States of America 0027-8424 Lan , T , Leppälä , K M , Tomlin , C , Talbot , S L , Sage , G K , Farley , S D , Shideler , R T , Bachmann , L , Wiig , Ø , Albert , V A , Salojärvi , 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 , vol. 119 , no. 24 , 2200016119 . https://doi.org/10.1073/pnas.2200016119 PURE: 227258738 PURE UUID: bcfa56f1-34b2-4454-8677-6c03b6bf3156 Scopus: 85131345690 PubMed: 35666863 WOS: 000852907500001 http://hdl.handle.net/10138/348204 cc_by_nc_nd openAccess info:eu-repo/semantics/openAccess 1181 Ecology evolutionary biology bear evolution climate change comparative genomics hybridization Ursus SEA-ICE PHYLOGEOGRAPHY POPULATION HISTORY ANCIENT ADMIXTURE REVEAL GENE FLOW BROWN BEARS URSUS-ARCTOS GRIZZLY BEARS Article publishedVersion 2022 ftunivhelsihelda https://doi.org/10.1073/pnas.2200016119 2023-11-23T00:01:26Z 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 10x 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. Peer reviewed Article in Journal/Newspaper Archipelago Arctic Climate change Sea ice Svalbard Ursus arctos Ursus maritimus Alaska HELDA – University of Helsinki Open Repository Arctic Svalbard Svalbard Archipelago Proceedings of the National Academy of Sciences 119 24 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
1181 Ecology evolutionary biology bear evolution climate change comparative genomics hybridization Ursus SEA-ICE PHYLOGEOGRAPHY POPULATION HISTORY ANCIENT ADMIXTURE REVEAL GENE FLOW BROWN BEARS URSUS-ARCTOS GRIZZLY BEARS |
spellingShingle |
1181 Ecology evolutionary biology bear evolution climate change comparative genomics hybridization Ursus SEA-ICE PHYLOGEOGRAPHY POPULATION HISTORY ANCIENT ADMIXTURE REVEAL GENE FLOW BROWN BEARS URSUS-ARCTOS GRIZZLY BEARS Lan, Tianying Leppälä, Kalle Matias Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojärvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis Lindqvist, Charlotte Insights into bear evolution from a Pleistocene polar bear genome |
topic_facet |
1181 Ecology evolutionary biology bear evolution climate change comparative genomics hybridization Ursus SEA-ICE PHYLOGEOGRAPHY POPULATION HISTORY ANCIENT ADMIXTURE REVEAL GENE FLOW BROWN BEARS URSUS-ARCTOS GRIZZLY BEARS |
description |
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 10x 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. Peer reviewed |
author2 |
Organismal and Evolutionary Biology Research Programme University of Helsinki |
format |
Article in Journal/Newspaper |
author |
Lan, Tianying Leppälä, Kalle Matias Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojärvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis Lindqvist, Charlotte |
author_facet |
Lan, Tianying Leppälä, Kalle Matias Tomlin, Crystal Talbot, Sandra L. Sage, George K. Farley, Sean D. Shideler, Richard T. Bachmann, Lutz Wiig, Øystein Albert, Victor A. Salojärvi, Jarkko Mailund, Thomas Drautz-Moses, Daniela I. Schuster, Stephan C. Herrera-Estrella, Luis 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 |
http://hdl.handle.net/10138/348204 |
geographic |
Arctic Svalbard Svalbard Archipelago |
geographic_facet |
Arctic Svalbard Svalbard Archipelago |
genre |
Archipelago Arctic Climate change Sea ice Svalbard Ursus arctos Ursus maritimus Alaska |
genre_facet |
Archipelago Arctic Climate change Sea ice Svalbard Ursus arctos Ursus maritimus Alaska |
op_relation |
https://doi.org/10.1073/pnas.2200016119 Proceedings of the National Academy of Sciences of the United States of America 0027-8424 Lan , T , Leppälä , K M , Tomlin , C , Talbot , S L , Sage , G K , Farley , S D , Shideler , R T , Bachmann , L , Wiig , Ø , Albert , V A , Salojärvi , 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 , vol. 119 , no. 24 , 2200016119 . https://doi.org/10.1073/pnas.2200016119 PURE: 227258738 PURE UUID: bcfa56f1-34b2-4454-8677-6c03b6bf3156 Scopus: 85131345690 PubMed: 35666863 WOS: 000852907500001 http://hdl.handle.net/10138/348204 |
op_rights |
cc_by_nc_nd openAccess info:eu-repo/semantics/openAccess |
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_ |
1785551105785069568 |