ミトコンドリア DNA の制限酵素切断型多型解析から見た北海道内におけるサクラマスの遺伝的変異性 Genetic Variability of Masu Salmon in Hokkaido, by Restriction Fragment Length Polymorphism Analysis of Mitochondrial DNA

北海道産サクラマス集団の遺伝的特性把握を目的に6河川, 8集団180個体についてmtDNAのRFLP解析を行い, 20のハプロタイプを検出した。ハプロタイプ間及び集団間の塩基置換率はそれぞれ0.14∿2.41%, 0.49∿0.70%であった。各河川集団間にはハプロタイプ頻度に有意差が認められる場合が多かった。本種の種苗放流を行う場合, 集団間の遺伝的差異を充分考慮するべきであると考えられた。

Mitochondrial DNA (mtDNA) of masu salmon among eight populations from six rivers around Hokkaido island were examined to clarify their genetic features and population structure. Restriction fragment length polymorphism (RFLP) analysis using 10 restriction endonucleases (Acc I, Ava I, BamH I, Bgl I, Bgl II, EcoR I, Hinc II, Hind III, Pst I, Xba I) revealed considerable variation. We found 20 haplotypes in 180 specimens. Restriction patterns were polymorphic for 7 enzymes examined. Nucleotide divergence among haplotypes ranged from 0.14 to 2.41%. Nucleotide divergence among populations ranged from 0.49 to 0.70%. Dendrogram constructed by UPGMA among 20 haplotypes showed no clustering groups of localities. Nucleotide diversity and nucleon diversity of each locality ranged from 0.0043 to 0.0072,and from 0.7617 to 0.9304,respectively. These results showed masu salmon populations in Hokkaido have a high mtDNA variability. It is important that high genetic variability be highly regarded in stock enhancement of masu salmon.