应用SSR分析5个三疣梭子蟹野生群体的遗传多样性

Genetic diversity among five wild populations of Portunus trituberculatus

利用本实验室筛选的8个微卫星分子标记,对中国舟山(ZS)、海州湾(HZ)、青岛会场(HC)、莱州湾(LZ)和鸭绿江口(YL)5个三疣梭子蟹(Portunus trituberculatus)野生群体共计120个个体进行了遗传多样性分析。结果显示,8个位点共扩增到72个等位基因,平均等位基因数为9.0,平均有效等位基因数为5.467 7;平均多态信息含量为0.696 7;平均期望杂合度(He)为0.750 8。5个群体的期望杂合度由高到低依次为LZ(0.770 4)、HC(0.758 8)、YL(0.755 2)、HZ(0.741 5)、ZS(0.728 3)。卡方检验可知,34个群体位点组合符合Hardy-Weinberg平衡,占总数的85%。5个群体间的遗传距离在0.245 1～0.517 9之间,HC和HZ的遗传距离最小,LZ和ZS的遗传距离最大;通过构建UPGMA聚类树,发现5个群体聚为南北两大支,HC和HZ两个群体遗传距离最近先聚到一起,再与ZS群体相聚,形成南方群体;YL与LZ群体相聚形成北方群体,最后南北两大群体聚为一支。分析群体间的Fst值可知,两两群体间的Fst值在0.054 8～0.108 3(0.05<Fst<0.15)之间,群体间产生了极显著的遗传分化。

We evaluated genetic diversity and differentiation among five wild populations of the swimming crab （Portunus trituberculatus） using eight polymorphic microsatellite loci. We collected crabs from Zhoushan （ZS）, Haizhou Bay （HZ）, Huichang （HC）, Laizhou Bay （LZ）, and the mouth of the Yalu River （YL）. We isolated 72 alleles from eight loci among the five populations. The number of alleles ranged from 6 to 12 and the average number of alleles （A） and effective numbers of alleles （Ne） were 9.0 and 5.467 7, respectively. The mean PIC value for the eight microsatellite loci was 0.696 7. The expected heterozygosity （He） of each population was as follows： LZ （0.770 4）, HC （0.758 8）, YL （0.755 2）, HZ （0.741 5）, and ZS （0.728 3）. The observed heterozygosity （Ho） was between 0.648 1 and 0.760 4. Six loci deviated significantly or very significantly from Hardy-Weinberg equilibrium. The genetic distances among populations ranged from 0.245 1 to 0.517 9. The UPGMA tree suggested that there were two different groups： one being composed of YL and LZ, and the other of HC, HZ and ZS. The Fst values ranged from 0.054 8 to 0.108 3, suggesting that the degree of differentiation was moderate among the five wild populations （0.05〈Fst〈0.15）.