GEOGRAPHIC-DISTRIBUTION OF MITOCHONDRIAL-DNA HAPLOTYPES IN GREY SEALS(HALICHOERUS-GRYPUS)

Mitochondrial DNA (mtDNA) variation in grey seals (Halichoerus grypus) was estimated by restriction fragment length polymorphism (RFLP) anal ysis of samples collected from four geographic locations: the Gulf of St. Lawrencn(n = 24), Sable Island, Nova Scotia (n = 20), Norway (n = 16), and the Baltic Sea (n = 20). In total, 18 haplotypes were identif ied. Nucleotide diversity was estimated to be 0.0039 for the Gulf of S t. Lawrence, 0.0035 for Sable Island, 0.0079 for Norway, and 0.0059 fo r the Baltic Sea. There were no shared haplotypes between the western North Atlantic and eastern North Atlantic groups, and genetic distance s between these populations (2.0-2.4%) suggest that they diverged appr oximately 1.0-1.2 million years ago. Nucleotide divergence between the Baltic Sea and the Norwegian populations was estimated to be 0.7%, su ggesting that separation of these two groups took place much more rece ntly, about 0.35 million years ago. The distribution of mtDNA haplotyp es among Canadian grey seals suggests little or no geographic separati on between animals breeding in the Gulf of St. Lawrence and those bree ding on Sable Island. In addition to providing basic information on st ock analysis the grey seal mtDNA RFLP analysis should be of value for further studies including polymerase chain reaction and direct sequenc e analyses.