Genetic divergence among natural populations of Ayu from Japan and Korea.

Abstract

Ten samples of amphidromous-form from Japan Islands, Ryukyu Islands, and Korean Peninsula, and three samples of landlocked-form from Lake Biwa were used for the population analysis of ayu Plecoglossus altivelis. Among 23 loci examined, 6 loci were polymorphic (lower than 0.95 in major allele frequency) in Japanese populations, 2 loci in Korean populations and 4 loci in Lake Biwa populations. The polymorphic locus of Ryukyu's population was only one, but the allele substitution was observed at five loci comparing with the other populations. Average heterozygosity ranged from 0.039 to 0.061 (0.051 on the average) in Japanese populations, 0.045-0.061 (0.054 on the average) in Lake Biwa, 0.027-0.039 (0.032 on the average) in Korean, and 0.011 in Ryukyu. Gpi-l100 and Mpi100 allele frequencies of Korean populations were slightly higher than those of Japanese populations. However, the level of genetic distance between them was very low (D=0.0012). On the other hand, the genetic distance between amphidromous and landlocked forms was relatively large (D=0.0197). The population of Ryukyu Islands was re-markably different from Japanese and Korean populations (D=0.2812).