Population genetic structure of pink salmon Oncorhynchus gorbuscha (Walbaum) inferred from the restriction enzyme analysis of mitochondrial DNA: Temporal heterogeneity at the period of spawning run

The restriction enzyme analysis of total mitochondrial DNA (mtDNA) and its fragments amplified by polymerase chain reaction (PCR) was employed in stud ying the variation in pink salmon Oncorhynchus gorbuscha of the even- and o dd-year generations from two rivers of Sakhalin. Samples of 30 fish each we re collected at an interval of 10-15 days during the spawning run. Using fo ur restriction enzymes, 2.15% of the pink salmon mitochondrial genome was e xamined. In total, 37 haplotypes with 18 polymorphic restriction sites were revealed in 449 fish. The haplotype frequencies significantly differed in samples collected at different periods of the spawning run. Molecular analy sis of variance (AMOVA, accounted for by Excoffer et al., 1992) showed that only a fraction of the total variance is accounted for by temporal variati on. This heterozygosity is probably explained by the subpopulation structur e of each of the river populations and random processes in subpopulations.