A COMBINED DNA-MICROSATELLITE AND ISOZYME ANALYSIS OF THE POPULATION-STRUCTURE OF THE HARBOR PORPOISE IN DANISH WATERS AND WEST GREENLAND

One hundred and twenty-four specimens of the harbour porpoise, Phocoen a phocoena, occurring in inner Danish waters (IDW), the North Sea and West Greenland were analysed to study subdivision into genetically dif ferentiated subpopulations using PCR-amplified DNA-microsatellites and isozyme markers. Three polymorphic microsatellites, 415/416, 417/418 and Igf-I (insulin-like growth factor I) were detected with nine, eigh t and 15 alleles, respectively, and from a former study two polymorphi c isozymes, Mpi-1 and Pgm, with three and two alleles, respectively, w ere used in the analysis. Overall deviations from the expected Hardy-W einberg distribution were only observed in the total sample and at a s ingle locus in the North Sea-summer sample and at two loci in the West Greenland sample. Whenever this occurred a surplus of homozygotes was observed, suggesting a Wahlund effect, a null allele or nonrandom mat ing. The analysis of the genetical population structure showed that ha rbour porpoises from West Greenland, the North Sea and IDW were three geographically, genetically differentiated populations even though con nected through some degree of gene flow. A tendency for females to be more stationary than males was suggested. Furthermore, the population structure suggested a closer relationship between IDW and the North Se a.