The Genetic Structure of Salmonid Populations

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In northern part of Japan, salmonid fish have commercial importance, and there are much effort of enhancement of salmonid populations. To maintain these populations in both economical and biological sense, management of salmonid populations is required. To achieve management goal development of stock identification methods is urgent task. In this project we investigated MHC gene, allozyme, and morphometrics and lectin of salmonid fish.1.MHC gene analysis We cloned MHC class1 gene using PCR method. Only alpha-1 domain was amplified for both chum and pink salmon.For pink salmon it is known that they have strict two year life cycle and genetic difference among year classes is greater than among populations within year from allozyme study. In this project we revealed amino sequence and also DNA size of MHC class alpha-1 domain differs between even and odd year samples of pink salmon from Hokkaido. In Alaskan sample these two different types of DNA sequence exist in single individual.Though it is necessary to validate based on large number of samples, we could identify the origin of fish for samples we analyzed based on MHC classl alpha-1 domain sequences.For chum salmon variations both within and between individuals are observed.2.Lectin L-Rhamnose was the most effective inhibitor of rainbow trout, chum, pink, sockeye, chinook salmon ova lectin. For chum salmon and rainbow trout lectin was purified by L-Rhamnose column. Amino acid sequences of these two species were determined and found identical except for a few undetermined amino acids.3.Allozyme study was also conducted as reference to MHC gene analysis. Amplification of mtDNA of chum salmon was successful using primer sets designed for coho salmon.4.Meristic Characters Meristic counts of several characters showed significant difference between Alaskan and Iwata population of pink salmon.