Genetic Diversity of Chinese Medaka (Oryzias sinensis) in Dian Lake Drainage Area by ISSR Analysis

Abstract

Chinese medaka(Oryzias sinensis), widely distributed in the plateau lakes, Yunnan Province, which was the indicative specie for the habitat quality of riparian zone in the wetland ecosystems and also was the key specie in the lake ecosystems, and also was one of the fishes who suffered the severe invasion of alien species. There, we investigated that the genetic diversity and population structure of the wild Chinese medaka by using inter-simple sequence repeat(ISSR) analysis. The samples(20 individuals in total) of Chinese medaka in three populations in the drainage area of Dian Lake were obtained. The 7 ISSR primers were picked out to assess the genetic diversity. The ISSR primers combinations revealed 82.69% polymorphism, among 52 genetic loci amplified. The sum of effective number of alleles and observed number of alleles were 1.492 4 and 1.826 9, respectively. The Shannon genetic diversity and Nei genetic diversity indexes of all the populations were 0.434 5 and 0.289 7, respectively. The gene differentiation(GST)was 0.198 9, and the gene flow(NM) was 2.013 2. The AMOVA demonstrated that only 6.65% of genetic variance came from inter-population, and 93.35% of genetic variance came from intra-population. Phylogenetic tree showed that 20 individuals from 3 populations were clustering mixed each other. Also, the principal coordinate analysis(PCA) supported the cluster analysis results. These results indicated that the genetic diversity of Oryzias sinensis was at the middle level, and there was no obvious genetic differentiation among the three populations of Oryzias sinensis.