Spatial genetic structure and asymmetrical gene flow within the Pacific walrus
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...
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fthighwire:oai:open-archive.highwire.org:jmammal:93/6/1512 2023-05-15T15:10:38+02:00 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. 2012-12-17 00:00:00.0 text/html http://jmammal.oxfordjournals.org/cgi/content/short/93/6/1512 https://doi.org/10.1644/11-MAMM-A-344.1 en eng Oxford University Press http://jmammal.oxfordjournals.org/cgi/content/short/93/6/1512 http://dx.doi.org/10.1644/11-MAMM-A-344.1 Copyright (C) 2012, Oxford University Press Feature Articles TEXT 2012 fthighwire https://doi.org/10.1644/11-MAMM-A-344.1 2016-11-16T18:58:39Z 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 (Φ ST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (Φ ST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite F ST = 0.019; mtDNA Φ ST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite F ST = 0.019–0.035; mtDNA Φ ST = 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. Text Arctic Bering Sea Chukchi Odobenus rosmarus Pacific Arctic St Lawrence Island walrus* HighWire Press (Stanford University) Arctic Bering Sea Pacific Lawrence Island ENVELOPE(-103.718,-103.718,56.967,56.967) Journal of Mammalogy 93 6 1512 1524 |
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HighWire Press (Stanford University) |
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language |
English |
topic |
Feature Articles |
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Feature Articles 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 |
Feature Articles |
description |
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 (Φ ST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (Φ ST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite F ST = 0.019; mtDNA Φ ST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite F ST = 0.019–0.035; mtDNA Φ ST = 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 |
Text |
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 |
publishDate |
2012 |
url |
http://jmammal.oxfordjournals.org/cgi/content/short/93/6/1512 https://doi.org/10.1644/11-MAMM-A-344.1 |
long_lat |
ENVELOPE(-103.718,-103.718,56.967,56.967) |
geographic |
Arctic Bering Sea Pacific Lawrence Island |
geographic_facet |
Arctic Bering Sea Pacific Lawrence Island |
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_relation |
http://jmammal.oxfordjournals.org/cgi/content/short/93/6/1512 http://dx.doi.org/10.1644/11-MAMM-A-344.1 |
op_rights |
Copyright (C) 2012, Oxford University Press |
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_ |
1766341623573118976 |