Study on the Genetic Structure of Three Cultured Populations of Takifugu obscurus with Microsatellite Markers

Abstract:

In recent years the aquaculture Takifugu obscurus has been impeded due to the adverse changes in the ecological environments and in the hydrological conditions of the Yangtze River. Here we evaluated the genetic diversity of three cultured populations of T. obscurus and hence provided theoretical data for the potential improvement in T. obscures genetics. We used 21 pairs of microsatellite primers to analyze the genetic variances between the populations with SSR molecular marker technique, and successfully amplified 19 microsatellite markers. In three populations of T. obscurus, the number of alleles (A) was 3−11 with an average of 6.58; the effective number of alleles (Ne) was 1.7−7.8 with an average of 4.5; the value of average observed heterozygosities was 0.156−1.000; the expected heterozygosities (He) was 0.399−0.876 and the mean polymorphic information content (PIC) ranged from 0.353 to 0.858. The mean polymorphic information content (PIC) followed the order of Guangzhou population (0.588) < Shanghai population (0.633) < Jiangsu population (0.655). The genetic diversity coefficients were 0.048, 0.062, and 0.076 respectively with an average of 0.081. There was moderate genetic differentiation among the three populations. The genetic distances between each population and the UPGMA dendrogram showed that Guangzhou population and Shanghai population had the most remote relationship (0.351), and that Guangzhou population and Jiangsu population were the closest (0.204). The three populations were pooled into 2 groups in the cluster analysis—the Guangzhou/Jiangsu group and the Shanghai group. These results suggested that there was a low level of polymorphism information content and moderate genetic diversity in the three populations of T. obscurus. Noticeably the genetic diversity of the farmed Jiangsu population was higher than that of the farmed Guangzhou and Shanghai populations, so there was a high potential in selective breeding. Our study broadened the knowledge on the genetics of T. obscurus and provided necessary information for the artificial breeding.