利用微卫星标记分析3个暗纹东方鲀(Takifugu obscurus)养殖群体的遗传多样性

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

关键词:  暗纹东方鲀  养殖群体  微卫星  遗传多样性

Key words:  Takifugu obscurus  Cultured population  Microsatellite  Genetic diversity

摘要:

针对3个暗纹东方鲀养殖群体，采用21对微卫星引物对其遗传多样性进行分析，成功扩增出具有一定多态性片段的微卫星位点共19个。共得到125个等位基因，每位点等位基因数为3−11，平均值为6.58，有效等位基因数为1.7−7.8，平均值为4.5，平均观测杂合度为0.156−1.000，平均期望杂合度为0.399−0.876，平均多态信息含量(PIC)为0.353−0.858。广州、上海、江苏3个群体的PIC由小到大依次为0.588、0.633、0.655，三群体间遗传分化指数分别为0.048、0.062、0.076，平均值为0.081，表明三群体间发生了小程度的遗传分化。三群体间的遗传距离和UPGAM分析显示，广州和上海群体的遗传距离最远(0.351)，广州和江苏群体的遗传距离最近(0.204)，聚类分析显示，广州群体和江苏群体聚为一类，上海群体为一类。研究结果基本符合养殖群体的养殖环境，也表明3个养殖群体发生了一定程度的遗传分化，特别是江苏群体的遗传多样性较高，作为选育群体具有一定的遗传潜力。

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.