Analysis of microsatellite DNA polymorphisms in rockfish Sebastes thompsoni and application to population genetics studies

Population differentiation and relationships among 6 natural rockfish popul ations collected from northern coastal seas around Japan were assayed using microsatellite DNA loci. Seven loci examined were polymorphic in all popul ations. The number of alleles per locus ranged from 6.7 to 9.3, and the ave rage of observed and expected heterozygosity ranged from 0.63 to 0.68, and from 0.66 to 0.69, respectively. The observed genotype frequencies at each locus were almost in agreement with Hardy-Weinberg expectations with two ex ceptions (P < .05). The allele frequencies of 16 population pairs were sign ificantly different (P < .05). Genetic distance (D-A) between 6 populations ranged from 0.03 to 0.08. According to a neighbor-joining tree generated f rom the D-A values, the 6 populations fell into 3 clusters. These clusters were correlated with the geographical positions of each population; larval dispersions due to water current were also found to have an effect on these results.