西施舌群体遗传结构及分化的RAPD分析

RAPD analysis of genetic structure and differentiation of Coelomactra antiquata

采用55个随机引物对西施舌(Coelomactra antiquata)5个群体,即长乐(CL)、启东(QD)、连云港(LYG)、胶南(JN)和北海(BH)群体进行RAPD扩增。用PopGen(Version1.32)软件进行遗传多样性分析。结果共筛选出12个重复性好的引物,得到88条清晰稳定的条带,扩增片段在100 bp～3 000 bp之间,其中引物S299扩增的600 bp片段为长乐群体特有。多态位点比例为62.07%～78.26%(JN、LYG、BH、QD、CL群体分别为78.26%、77.05%、72.58%、70.05%、62.07%),Shannon指数为0.210 5～0.312 3。群体间遗传距离为0.068 3～0.223 9,其中长乐群体与其余4个群体间的遗传距离为0.182 7～0.223 9,4个非长乐群体的遗传距离为0.068 3～0.136 7。群体间遗传分化系数(Fst)为0.313 01(P<0.05),表明在整个遗传变异中群体间占31.30%。CL群体与QD,BH,JN,LYG群体间的遗传分化系数(Gst)分别为0.364 9,0.344 8,0.325 0,0.309 0;而非长乐群体之间的遗传分化系数为0.148 2～0.240 3;以上数据显示长乐群体遗传分化最大。聚类结果显示,启东和胶南群体首先聚为一支,然后与北海群体聚在一起,再和连云港群体相聚;而长乐群体则单独形成一支。

The Randomly Amplified Polymorphic DNA（RAPD） technique was applied to assess the genetic variations among five stocks [Changle（CL）,Qidong（QD）,Lianyungang（LYG）,Shandong（JN） and Guangxi（BH）] of Coelomactra antiquata using 55 random primers.Genetic diversity was analyzed with PopGen（Version 1.31） software.A total of 12 highly reproducible primers and 88 clear and stable bands were obtained.The lengths of amplified fragments were from 100 bp to 3000 bp.The primer S299,which amplified 600 bp fragment,was specific to the CL stock.The proportion of polymorphic loci was from 62.07% to 78.26% and Shannon index was from 0.210 5 to 0.312 3.Genetic distance among five stocks was from 0.068 3 to 0.223 9.The genetic distance between the CL stock and the other four stocks was 0.182 7～0.223 9,and the genetic distance among the four non-CL stocks was 0.068 3～0.136 7.Coefficient of genetic differentiation among stocks（Fst） was 0.31301（P 0.05）,indicating the genetic variation among stocks accounted for 31.30%.The value of genetic differentiation（Gst） between CL and the other four stocks were 0.364 9,0.344 8,0.325 0,and 0.309 0 for QD,BH,JN,and LYG,respectively.The values of genetic differentiation（Gst） among non-CL stocks were 0.148 2～0.240 3.The above data show that the maximum genetic differentiation occurred in the CL stock.Phylogenetic analysis shows that QD and JN stocks formed a clade,which subsequently clustered with BH stock,and then got together with LYG stock.Meanwhile CL stock formed one separate clade.