Meeting Abstract
Following the retreat of the Last Glacial Maximum in the North Atlantic about 20,000 years ago, two sibling species of sea stars, Asterias rubens and A. forbesi , expanded their ranges from glacial refuges in Europe and the southeastern United States, respectively. To examine the effects of post-glacial migration on species population genetics and gene flow, Asterias rubens was sampled from 15 populations across the North Atlantic, from northeastern Canada to Russia. Endemic to North America, Asterias forbesi , was sampled from 9 populations from Prince Edward Island to North Carolina. Mitochondrial DNA sequences of the cytochrome oxidase I gene (586 bp) were obtained following PCR reactions with extracted genomic DNA, and analyzed together with sequences available on GenBank. In A. rubens populations, while we found 19 different haplotypes from 107 individuals across the species’ range, most individuals (71%) had the same haplotype. Similarly, in A. forbesi populations, we found 16 different haplotypes from 87 individuals, with most individuals (80%) having one of only two main haplotypes. In phylogenetic analysis with both species, haplotypes did not form monophyletic groups with respect to sampling location, as many geographically separate populations shared identical haplotypes. No significant genetic structure or genetic discontinuity was found across either species’ range, which is indicative of recent population expansions in both species.
