Abstract

A restriction enzyme analysis of mitochondrial DNA was performed on 55 Eiders from several Baltic and one Icelandic localities. The overall nucleotide diversity was moderate (pi = 0.32%). No additional genetic variation was found among regions (Iceland vs. Baltic Sea), suggesting a postglacial colonization of Iceland from continental Europe. The lack of correlation between the relatedness of haplotypes and their geographic distribution and the high percentage of haplotypes unique for single colonies (57-100%) is probably an effect of lineage sorting due to founder effects and subsequent genetic drift in elder colonies. In all cases, estimated gene flow among colonies was less than one female per generation, which is corroborated by the known female philopatry in Eiders. For nuclear genes, gene flow among colonies is expected due to migrating males.