These authors contributed equally to this work.
Article first published online: 12 APR 2012
© 2012 Blackwell Publishing Ltd
Volume 21, Issue 11, pages 2775–2787, June 2012
How to Cite
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: 2775–2787. doi: 10.1111/j.1365-294X.2012.05572.x
- Issue published online: 24 MAY 2012
- Article first published online: 12 APR 2012
- Received 24 August 2011; revised received 9 February 2012; accepted 16 February 2012
- circumpolar distribution;
- glacial cycles;
- population structure;
- southern ocean
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 Adélie Land. The mean age of mtDNA diversity within these main continental lineages coincides with Pleistocene glacial cycles.