북태평양 연어 (Oncorhynchus keta)의 집단간 유전자 확산 정도 산정

Abstract

The chum salmon is an anadromous fish distributed in the North Pacific. It has long been a common belief that the released salmons return back to their home rivers when they become mature.  As an attempt to examine the extent of their homing behavior, here we inferred the phylogenetic relationships among the individuals of different populations and estimated the rate of gene flow between the populations.  For this, sequences of the COIII‐ND3‐ND4L region (744 nucleotides) of the mitochondrial DNA were obtained from Korea (35 individuals, Namdae river; 13, Wangpi river), Japan (20, Hakodade; 24, Shokanbetsu river), Canada (14, Nitnat river; 15, Fraser river), and the United States chum salmons (20, Quilcene). The 141 sequences comprise 45 different haplotypes of which are a haplotype shared by approximately 50% of Korea and Japan individuals, a haplotype by Japan and Canada, a haplotype by Canada and the United States, and a haplotype by individuals from all the four populations, indicating presence of migration among the populations. The TCS network diagram of the haplotype genealogies corroborates such gene flow and shows close relationships between the Korea and the Japan populations and between the Canada and the United States populations. Major gene flows determined by MIGRATE are observed from the United States to the Canada populations (16±6 individuals per generation) and from the Japan to the Korea populations (12±7). Between the East and the West Pacific populations gene flow is relatively minimal.