Spatial genetic structure and asymmetrical gene flow within the Pacific walrus
Abstract Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations...
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Online Access: | http://dx.doi.org/10.1644/11-mamm-a-344.1 http://academic.oup.com/jmammal/article-pdf/93/6/1512/30297970/93-6-1512.pdf |
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croxfordunivpr:10.1644/11-mamm-a-344.1 2024-05-12T08:00:22+00:00 Spatial genetic structure and asymmetrical gene flow within the Pacific walrus Sonsthagen, Sarah A. Jay, Chadwick V. Fischbach, Anthony S. Sage, George K. Talbot, Sandra L. 2012 http://dx.doi.org/10.1644/11-mamm-a-344.1 http://academic.oup.com/jmammal/article-pdf/93/6/1512/30297970/93-6-1512.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by-nc-nd/3.0/ Journal of Mammalogy volume 93, issue 6, page 1512-1524 ISSN 1545-1542 0022-2372 Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics journal-article 2012 croxfordunivpr https://doi.org/10.1644/11-mamm-a-344.1 2024-04-18T08:18:17Z Abstract Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations and 6 nonbreeding aggregations. Analyses of mitochondrial DNA (mtDNA) control region sequence data suggest that males are distinct among breeding populations (ΦST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (ΦST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite FST = 0.019; mtDNA ΦST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite FST = 0.019–0.035; mtDNA ΦST = 0.386–0.389). Gene flow estimates are asymmetrical from St. Lawrence Island into the southeastern Bering breeding population for both sexes. Partitioning of haplotype frequencies among breeding populations suggests that individuals exhibit some degree of philopatry, although weak. High levels of genetic differentiation among eastern Chukchi and all other nonbreeding aggregations, but considerably lower genetic differentiation between breeding populations, suggest that at least 1 genetically distinct breeding population remained unsampled. Limited genetic structure at microsatellite loci between assayed breeding areas can emerge from several processes, including male-mediated gene flow, or population admixture following a decrease in census size (i.e., due to commercial harvest during 1880–1950s) and subsequent recovery. Nevertheless, high levels of genetic diversity in the Pacific walrus, which withstood prolonged decreases in census numbers with little impact on neutral genetic diversity, may reflect resiliency in the face of past environmental challenges. Article in Journal/Newspaper Arctic Bering Sea Chukchi Odobenus rosmarus Pacific Arctic St Lawrence Island walrus* Oxford University Press Arctic Bering Sea Lawrence Island ENVELOPE(-103.718,-103.718,56.967,56.967) Pacific Journal of Mammalogy 93 6 1512 1524 |
institution |
Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics Sonsthagen, Sarah A. Jay, Chadwick V. Fischbach, Anthony S. Sage, George K. Talbot, Sandra L. Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
topic_facet |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics |
description |
Abstract Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations and 6 nonbreeding aggregations. Analyses of mitochondrial DNA (mtDNA) control region sequence data suggest that males are distinct among breeding populations (ΦST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (ΦST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite FST = 0.019; mtDNA ΦST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite FST = 0.019–0.035; mtDNA ΦST = 0.386–0.389). Gene flow estimates are asymmetrical from St. Lawrence Island into the southeastern Bering breeding population for both sexes. Partitioning of haplotype frequencies among breeding populations suggests that individuals exhibit some degree of philopatry, although weak. High levels of genetic differentiation among eastern Chukchi and all other nonbreeding aggregations, but considerably lower genetic differentiation between breeding populations, suggest that at least 1 genetically distinct breeding population remained unsampled. Limited genetic structure at microsatellite loci between assayed breeding areas can emerge from several processes, including male-mediated gene flow, or population admixture following a decrease in census size (i.e., due to commercial harvest during 1880–1950s) and subsequent recovery. Nevertheless, high levels of genetic diversity in the Pacific walrus, which withstood prolonged decreases in census numbers with little impact on neutral genetic diversity, may reflect resiliency in the face of past environmental challenges. |
format |
Article in Journal/Newspaper |
author |
Sonsthagen, Sarah A. Jay, Chadwick V. Fischbach, Anthony S. Sage, George K. Talbot, Sandra L. |
author_facet |
Sonsthagen, Sarah A. Jay, Chadwick V. Fischbach, Anthony S. Sage, George K. Talbot, Sandra L. |
author_sort |
Sonsthagen, Sarah A. |
title |
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
title_short |
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
title_full |
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
title_fullStr |
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
title_full_unstemmed |
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus |
title_sort |
spatial genetic structure and asymmetrical gene flow within the pacific walrus |
publisher |
Oxford University Press (OUP) |
publishDate |
2012 |
url |
http://dx.doi.org/10.1644/11-mamm-a-344.1 http://academic.oup.com/jmammal/article-pdf/93/6/1512/30297970/93-6-1512.pdf |
long_lat |
ENVELOPE(-103.718,-103.718,56.967,56.967) |
geographic |
Arctic Bering Sea Lawrence Island Pacific |
geographic_facet |
Arctic Bering Sea Lawrence Island Pacific |
genre |
Arctic Bering Sea Chukchi Odobenus rosmarus Pacific Arctic St Lawrence Island walrus* |
genre_facet |
Arctic Bering Sea Chukchi Odobenus rosmarus Pacific Arctic St Lawrence Island walrus* |
op_source |
Journal of Mammalogy volume 93, issue 6, page 1512-1524 ISSN 1545-1542 0022-2372 |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/3.0/ |
op_doi |
https://doi.org/10.1644/11-mamm-a-344.1 |
container_title |
Journal of Mammalogy |
container_volume |
93 |
container_issue |
6 |
container_start_page |
1512 |
op_container_end_page |
1524 |
_version_ |
1798842241204092928 |