Population differentiation in the context of Holocene climate change for a migratory marine species, the southern elephant seal

Abstract Understanding observed patterns of connectivity requires an understanding of the evolutionary processes that determine genetic structure among populations, with the most common models being associated with isolation by distance, allopatry or vicariance. Pinnipeds are annual breeders with th...

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Bibliographic Details
Published in:Journal of Evolutionary Biology
Main Authors: Corrigan, L. J., Fabiani, A., Chauke, L. F., McMahon, C. R., de Bruyn, M., Bester, M. N., Bastos, A., Campagna, C., Muelbert, M. M. C., Hoelzel, A. R.
Other Authors: Office of Polar Programs, National Science Foundation, Department of Science and Technology, Government of Kerala, National Research Foundation
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2016
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Online Access:http://dx.doi.org/10.1111/jeb.12870
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https://onlinelibrary.wiley.com/doi/pdf/10.1111/jeb.12870
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Summary:Abstract Understanding observed patterns of connectivity requires an understanding of the evolutionary processes that determine genetic structure among populations, with the most common models being associated with isolation by distance, allopatry or vicariance. Pinnipeds are annual breeders with the capacity for extensive range overlap during seasonal migrations, establishing the potential for the evolution of isolation by distance. Here, we assess the pattern of differentiation among six breeding colonies of the southern elephant seal, Mirounga leonina , based on mt DNA and 15 neutral microsatellite DNA markers, and consider measures of their demography and connectivity. We show that all breeding colonies are genetically divergent and that connectivity in this highly mobile pinniped is not strongly associated with geographic distance, but more likely linked to Holocene climate change and demographic processes. Estimates of divergence times between populations were all after the last glacial maximum, and there was evidence for directional migration in a clockwise pattern (with the prevailing current) around the Antarctic. We discuss the mechanisms by which climate change may have contributed to the contemporary genetic structure of southern elephant seal populations and the broader implications.