Persistent genetic signatures of historic climatic events in an Antarctic octopus

Strugnell, J.M., Watts, P.C., Smith, P.J., and Allcock, A.L. (2012) Persistent genetic signatures of historic climatic events in an Antarctic octopus. Molecular Ecology, 21 (11). pp. 2775-2787.

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Repeated cycles of glaciation have had major impacts on the distribution of genetic diversity of the Antarctic marine fauna. During glacial periods, ice cover limited the amount of benthic habitat on the continental shelf. Conversely, more habitat and possibly altered seaways were available during interglacials when the ice receded and the sea level was higher. We used microsatellites and partial sequences of the mitochondrial cytochrome oxidase 1 gene to examine genetic structure in the direct-developing, endemic Southern Ocean octopod Pareledone turqueti sampled from a broad range of areas that circumvent Antarctica. We find that, unusually for a species with poor dispersal potential, P. turqueti has a circumpolar distribution and is also found off the islands of South Georgia and Shag Rocks. The overriding pattern of spatial genetic structure can be explained by hydrographic (with ocean currents both facilitating and hindering gene flow) and bathymetric features. The Antarctic Peninsula region displays a complex population structure, consistent with its varied topographic and oceanographic influences. Genetic similarities between the Ross and Weddell Seas, however, are interpreted as a persistent historic genetic signature of connectivity during the hypothesized Pleistocene West Antarctic Ice Sheet collapses. A calibrated molecular clock indicates two major lineages within P. turqueti, a continental lineage and a sub-Antarctic lineage, that diverged in the mid-Pliocene with no subsequent gene flow. Both lineages survived subsequent major glacial cycles. Our data are indicative of potential refugia at Shag Rocks and South Georgia and also around the Antarctic continent within the Ross Sea, Weddell Sea and off Adelie Land. The mean age of mtDNA diversity within these main continental lineages coincides with Pleistocene glacial cycles.

Item ID: 46366
Item Type: Article (Research - C1)
ISSN: 1365-294X
Keywords: circumpolar distribution, glacial cycles, octopod, population structure, southern ocean
Funders: NERC, Lloyd's Tercentenary Fellowship, CoSyst, Antarctic Science Bursary, Systematics Association, Edith Mary Pratt Musgrave Fund, Australia and Pacific Science Foundation, New Zealand Government
Projects and Grants: NERC AFI NE⁄C506321/1, NZ International Polar Year-Census of Antarctic Marine Life Project
Date Deposited: 16 Nov 2016 07:45
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 100%
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