Local and Temporal Variation at the MHC I-A1 Locus in Pink Salmon Oncorhynchus gorbuscha of Southern Sakhalin

In order to test the MHC I-A1 locus of the main histocompatiblity complex as an effective molecular marker for identification of populations of Far Eastern pink salmon, Oncorhynchus gorbuscha, the comparison of the allelic and genotypic frequencies between two neighboring populations of the Lyutoga and Taranay rivers (Aniva Bay, Sakhalin Island), as well as within the populations: within generation, between adjacent and distant generations, have been performed. It was revealed that temporal variation at MHC I-A1 is statistically insignificant in comparison between the samples of the juveniles sampled at different times during the downstream migration. It is also insignificant between the samples of juvenile and adult fish of the same generation, and between samples divided by a single and seven generations. At the same time, the samples of neighboring populations differ significantly. The possibility of differentiation of the populations on the local scale and temporal stability of the allele frequencies indicate the MHC I-A1 as valuable marker for the development of the population data bases. Inclusion of the MHC I-A1 into the panel of other markers (microsatellites, in particular) allows for considerable increase in the resolution power for identification as to which population an individual in the mixed sea catch belongs.