4个暗纹东方鲀群体的遗传多样性分析

Analysis of genetic diversity in four Takifugu obscurus populations

采用10对暗纹东方鲀(Takifugu obscurus)和16对红鳍东方鲀(Takifugu rubripes)微卫星引物对4个暗纹东方鲀群体(1个长江常熟江段捕捞群体,1个江苏扬中放流群体和2个养殖群体)的遗传多样性进行分析。结果显示,20个微卫星位点能成功扩增出片段并且具有一定的多态性,在4个群体中共检测到113个等位基因。每个群体的平均等位基因数为4.95～5.50,平均观测杂合度为0.686 7～0.761 7,平均期望杂合度为0.653 0～0.700 0,平均多态信息含量为0.601 3～0.638 4。各个群体都有一些微卫星位点偏离Hardy-Wein-berg平衡(P<0.05),主要表现为杂合子不足。群体间遗传分化系数为0.040 6,基因流值为5.905 6,群体间遗传分化程度较小,群体间基因流水平较高。4个群体间的遗传相似系数为0.859 0～0.915 8,遗传距离为0.088 0～0.151 9,采用UPGMA法对4个群体进行聚类,可分2类:上海养殖群体单独为一类,扬中放流群体、常熟江段捕捞群体和南通养殖群体为另一类。

Ten microsatellite primers of Takifugu obscurus and sixteen microsatellite primers of Takifugu rubripes were used to investigate genetic diversity of four T. obscurus populations （one wild population from Changshu,one released population from Yangzhong and two cultured populations from Nantong and Shanghai respectively） in this study. Twenty microsatellite markers were amplified suc- cessfully and a total of 113 alleles were detected in the four populations. In these populations the average number of alleles was from 4. 95 to 5. 50, the value of average observed and expected heterozygosity ranged from 0. 686 7 to 0. 761 7 and from 0. 653 0 to 0. 700 0 respectively,and the mean polymorphic in- formation content was from 0. 601 3 to 0. 638 4. Several loci were found to deviate from Hardy-Weinberg Equilibrium in each population, which indicated that the deficiency of heterozygote existed in the four populations. The value of genetic differentiation coefficient and gene flow were 0. 040 6 and 5. 905 6 re- spectively. These results suggested that the four populations have a low level of differentiation and great gene exchange among them. The genetic similarity coefficient of the four populations was from 0. 859 0 to 0. 915 8 and the genetic distance was from 0, 088 0 to 0. 151 9. Cluster analysis using the UPGMA method showed that Shanghai population formed an independent cluster and the other three populations formed another cluster.