我国沿海缢蛏群体遗传结构的mtDNA-COⅠ分析

Population Genetic Structure of Sinonovacula constricta along the Coast of China

采集了我国沿海共计9个缢蛏(Sinonovacula constricta)地理群体的197个样本,分别是北部组群的3个群体:辽宁省庄河群体(ZH),天津市汉沽群体(HG),山东省海阳群体(HY);中部组群的3个群体:江苏省盐城群体(YC),上海市崇明县东滩群体(DT)和堡镇群体(BZ);以及南部组群的3个群体:浙江省宁波群体(NB),浙江省台州群体(TZ)以及福建省宁德群体(ND)。利用线粒体COⅠ标记分析了9个群体的遗传多样性和遗传分化。结果表明,在共计197个个体中检测到125个单倍型和96个变异位点,核苷酸多样性指数位于2.1764～7.4970之间,其中中部组群的群体遗传多样性指数最高。AMOVA分析结果显示,组间遗传变异量占总变异的80.27%,18.74%来自于群体内,只有0.99%来自于组内群体间。群体间遗传分化系数位于0.0219～0.8706之间,不同群体间具有一定的遗传分化,尤其是中部群体与其他群体间遗传分化值达到了0.8以上,为极高度分化。遗传距离和聚类结果显示,北部3群体和南部3群体首先聚在一起,之后与中部3群体聚类。

The Razor Clam （Sinonovacula constricta）is an important shellfish in China,Japan and Korea. We sequenced mitochondrial cytochrome oxidase Ⅰ （ CO Ⅰ） genes of 197 individuals from nine populations to investigate population genetic structure of the northern （ZH,HG,HY）,the mid-regional（YC,DT,BZ） and the southern（NB,TZ,ND）groups of S. constricta along the coast of China. We identified 125 haplotypes and 96 variable sites from 556 bp of CO Ⅰ. Nucleotide diversity ranged from 2. 176 4 to 7. 497 0. Analysis of molecular variance （ AMOVA） showed that interpopulation variance accounted for 80. 27% （ P 0. 05 ）, whereas the remaining 18. 74% and 0. 99% were detected within population and among populations of same groups respectively,indicating significant genetic differentiation among populations. Phylogenetic tree analysis and genetic distance analysis showed that the nine populations were clustered into three distinct groups,with the northern group clustering first with the southern group and then with the mid-regional group.