Multiple ice-age refugia in Pacific cod, Gadus macrocephalus

• DOI: 10.1111/j.1365-294x.2010.04815.x
• Publication Date: 2010-09-05T07:21:57Z
• Authors: MICHAEL F. CANINO; INGRID B. SPIES; KATHRYN M. CUNNIN...; LORENZ HAUSER; W. STEWART GRANT
• Keywords: Last Glacial Maximum; mtDNA control region; Deglaciation

Pleistocene ice-ages greatly influenced the historical abundances of Pacific cod, Gadus macrocephalus, in North and its marginal seas. We surveyed genetic variation at 11 microsatellite loci mitochondrial (mt) DNA samples from twelve locations Sea Japan to Washington State. Both (mean H = 0.868) mtDNA haplotype h 0.958) diversities were large did not show any geographical trends. Genetic differentiation between was significantly correlated with distance for both microsatellites (FST 0.028, r2 0.33) 0.027, 0.18). marker classes showed a strong discontinuity northwestern northeastern populations that likely represents groups previously isolated during glaciations are now secondary contact. Significant differences appeared Okhotsk may reflect ice-age isolations northwest Pacific. In northeast Pacific, partition detected coastal Georgia Basin populations. The presence two major lineages on either side Ocean basin implies least refugia separate postglacial population expansions facilitated by different glacial histories. Northward into Gulf Alaska possible 14–15 kyr ago, but deglaciation colonization probably occurred somewhat later. Population evident mismatch distributions Bayesian skyline plots three lineages, start pre-date last maximum.