Genetic homogeneity among geographically distant populations of the blister worm Polydora websteri

Analysis of genetic variation at the mitochondrial cytochrome c oxidase I indicates there is no differentiation between blister worm populations, worldwide. It is unlikely that natural dispersal alone can account for this lack of differentiation; rather, our results are consistent with the hypothesis that human-mediated introductions (including aquaculture-based movement of shellfish hosts) have led to genetic homogeneity across large geographic distances for this pest polychaete species.