长江中上游南方鲇遗传多样性的RAPD分析

采用随机扩增多态性DNA(RAPD)技术对取自长江中上游合川、木洞、涪陵、彭水、巫山、宜昌及岳阳7个江段的南方鲇(Silurus meridionalisChen)野生群体的遗传多样性进行了分析,24个随机引物共检测出327个位点(200~2500 bp)。各群体的多态位点比例在28.75%~48.62%之间,基因多样性指数为0.2047~0.3074。遗传距离显示长江中上游南方鲇各群体间有一定遗传分化,其中,木洞和合川群体间遗传距离最小为0.0537),而合川和岳阳群体间的遗传距离最大(0.1205),群体间遗传分化系数为0.1866。聚类分析(UPGMA)显示,7个群体聚为两大类群,合川和木洞亲缘关系最近,首先聚在一起,之后与彭水、涪陵、巫山群体相继聚类形成类群Ⅰ,岳阳和宜昌群体则聚类形成类群Ⅱ。Shannon指数分析表明,长江中上游南方鲇野生群体间种质资源状况良好,遗传多样性水平较高。

Studies on Genetic Diversity of Southern Catfish(Silurus meridionalis Chen)in Yangtze River with RAPD

The Random Amplification of Polymorphic DNA(RAPD)technique was employed to detect the genetic diversity of Silurus meridionalis Chen.Samples were collected from Hechuan(HC),Mudong(MD),Fuling(FL),Pengshui(PS),Wushan(WS),Yichang(YC)and Yueyang(YY).Under predetermined optimal reaction conditions,327 RAPD sites(200～2500bp)were detected with 24 primers.Proportion range of polymorphic loci of each population was from 28.75% to 48.62% and genetic diversity was from 0.2047 to 0.3074.Among the seven wild populations,the farthest genetic distance(0.1205)occurred between the YY and HC populations,and the nearest distance(0.0537)occurred between the MD and HC populations.The mean index of genetic diversity rang of the populations was 0.1866.The result of unweighted pair-group method with arithmetic means(UPGMA)phenogram showed that the investigated seven wild Southern catfish populations were divided into two groups.Within the clusters,MD was closely related to HC and should be clustered firstly,then PS,FL and WS were clustered with MD-HC.Meanwhile,YC and YY were clustered into another group.The high level of mean heterozygosities between populations suggested that the resource of the wild S.meridionalis in the Yangtze River was in good condition with relatively higher genetic diversity.