Microsatellite analysis of the population structure of a Vancouver Island sockeye salmon (Oncorhynchus nerka) stock complex using nondenaturing gel electrophoresis

Variation at four microsatellite loci, Omy77, Ots100, Ots3, and Ots103, was characterized for three populations of sockeye salmon (Oncorhynchus nerka) found within 50 km of each other in the Barkley Sound region of Southwest Vancouver Island, British Columbia. We used a simple polyacrylamide gel ele ctrophoresis technique to analyze microsatellite alleles amplified from tot al genomic DNA extracts of liver and archived scales. Classes from several years were examined for each population, with little significant interannua l variability detected. Each microsatellite locus was highly polymorphic wi th 10 alleles at Omy77, 12 alleles at Ots100, 16 alleles at Ots3, and 17 al leles at Ots103; average observed heterozygosities were also high at 75%, 7 6%, 69%, and 85% respectively. F-st values and pairwise tests indicated tha t the populations had significantly different allele frequencies, suggestin g that the three populations are reproductively isolated. Our results sugge sted that microsatellite loci can be analyzed with a simple technique to re veal population structure of sockeye salmon on a small geographic scale.