浙闽沿海缢蛏群体遗传结构的微卫星和线粒体COⅠ序列分析

Microsatellites and mitochondrial COⅠ analysis of population genetic structure of Sinonovacula constricta along the coast of Zhejiang and Fujian Provinces

我国缢蛏养殖规模不断扩大,而缢蛏主产区苗种的遗传结构却缺乏系统的分析研究。利用微卫星标记和线粒体COⅠ序列分析了我国浙闽沿海8个缢蛏群体的遗传多样性和遗传分化水平。基于微卫星标记的遗传多样性分析结果显示,群体的平均有效等位基因数(Ne)为6.2～9.0,期望杂合度(He)为0.806～0.875;基于线粒体COⅠ标记的遗传多样性结果显示,单倍型多态性(Hd)为0.942～1.000,核苷酸多样性指数(P)为0.005 6～0.011 5。基于微卫星标记的群体间遗传分化值(FST)为0.001 4～0.063 8,除NH和SM群体外,其他群体间均具有显著性差异;基于线粒体COⅠ标记的群体间遗传分化值(FST)为0.000 9～0.368 0,部分群体间具有显著性差异。基于微卫星标记和线粒体COⅠ标记的聚类结果表明,位于同一海湾内的群体首先聚类在一起,但是浙江和福建沿海8群体并不符合地理距离隔离模式的聚类方式,而呈现出浙江群体和福建群体的交叉聚类。由此可见,我国缢蛏主产区浙闽沿海群体仍具有较高的遗传多样性水平,但是异地群体间产生了基因交流,并形成了新的地方性种群。

The razor clam,Sinonovacula constricta,which belongs to Mollusca,Bivalvia,Veneroida,Solecurtidae,is a common shellfish as human seafood,living in the lower-to-mid intertidal zones along the coast of the West Pacific Ocean.The genetic structure of the razor clam has not been reported along the coast of Zhejiang and Fujian Provinces,the major aquaculture regions in China following the widespread culture.In this study,genetic structure of eight populations of S.constricta from Zhejiang and Fujian Provinces（NH,SM,YH,YQ,CL,HJ,HA and SS）was estimated by using microsatellite loci and mitochondria COⅠ sequences.Based on microsatellite loci,the effective allele gene（Ne）number ranged from 6.2 to 9.0,and the expected heterozygosity（He）was high,ranging from 0.806 to 0.875.Based on mitochondria COⅠ,haplotype diversity（Hd）ranged from 0.942 to 1.000 and nucleotide diversity（P）varied from 0.005 6 to 0.011 5.The analysis of genetic differentiation revealed that the FST values ranged from 0.001 4 to 0.063 8 based on microsatellite loci and from 0.000 9 to 0.368 0 based on mitochondria COⅠ.The phylogenetic tree analyses showed that the genetic relationships of eight populations were not consistent with a model of isolation by distance（IBD）,but the populations within one bay could be clustered first.It is suggested that the razor clam contains high genetic diversity,but gene flow exists between Zhejiang populations and Fujian populations based on the genetic relationship.