1Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, 2Department of Human & Environment Faculty of Human Environment, Osaka Sangyo University, Daito, Osaka 574-8530, 3Collenge of Liberal Arts and Science, Osaka University of Economics and Law, Yao, Osaka 581-8511, Japan
Genetic characteristics of ten pond populations of Japanese rosy bitterling Rhodeus ocellatus kurumeus in Osaka Prefecture, Japan were evaluated with eight microsatellite markers. Although averaged allelic richness was about two in all the populations surveyed, two genetic parameters of heterozygosity and genetic relatedness differed greatly among populations, which seemed to be affected by founder effect and habitat size, respectively. In spite of homogeneity in allele composition among populations, genetic differentiation was observed between the northern and southern populations. These results suggest that Osaka populations of R. o. kurumeus with a monophyletic origin might have repeatedly suffered from founder and genetic bottleneck effects leading to genetic differentiation among populations, showing the importance of the carrying capacity of the environment for avoiding inbreeding.