中文摘要：

采用形态特征分析和RAPD技术对采自广西北海、防城和广东湛江的施氏獭蛤Lutraria siebaldii 3个自然群体和越南大獭蛤Lutraria maxima 1个群体的遗传多样性进行分析。结果表明：用20条引物从施氏獭蛤3个群体和越南大獭蛤1个群体的145个样品中共扩增出428条带,大小为125～5 000 bp,每条引物扩增出6～17条带;多态位点比例为76.1%～91.9%,平均多态位点比例为84.5%,遗传距离为0.1321～0.2441;对施氏獭蛤3个群体和大獭蛤1个群体进行UPGMA聚类分析,施氏獭蛤北海群体和防城群体先聚为一体,再与湛江群体聚类,最后与越南的大獭蛤群体聚为一个整体;用8条引物可以区分施氏獭蛤3个自然群体和大獭蛤群体,可作为群体特征标记;形态差异分析结果显示,湛江、北海和防城施氏獭蛤3个群体的形态较接近,而越南大獭蛤群体的外部形态和遗传距离均与施氏獭蛤3个群体差异较大,已分化成为同属不同种;主成分分析表明,主成分1、主成分2和主成分3的贡献率分别为49.13%、17.18%和14.02%,累计贡献率为80.33%;施氏獭蛤3个群体判别函数的判别准确率P1为88.9%～100.0%,P2为86.7%～100.0%,综合判别率为95.9%。这说明施氏獭蛤3个群体的遗传多样性均处于较高水平,种质状况良好,且具有很好的养殖前景。

英文摘要：

The random amplified polymorphic DNA（RAPD） technique and the morphological variation analysis were used to evaluate population genetics among three wild populations of clam Lutraria siebaldii in coastal Guangxi and Guangdong provinces and one population Lutraria maxima in coastal Vietnam.A total of 428 scorable markers were amplified from 20 RAPD primers in 145 samples from different populations of Lutraria siebaldii and Lutraria maxima,ranging from 125 to 5 000 bp in size,and the number of the scorable bands for each primer varied from 6 to 17,with the average polymorphic band proportion of 84.5%.The mean percent of polymorphic loci in four populations were ranged from 76.1% to 91.9% with genetic distance from 0.1321 to 0.2441 among individuals.The cluster analysis according to their genetic distances,first Zhanjiang,Beihai and Fangcheng populations,and then with Vietnam population,revealed that the 3 wild populations of Lutraria siebaldii were distinguished by 8 primers.The morphological variations showed that the samples from Zhanjiang,Beihai and Fangcheng populations were rather similar in morphology,whereas Vietnam population differed greatly from the other populations in morphology,indicating that these clams were divided into different species.In the principal component analysis,the contributory ratio of the three principal components was 49.13%,17.18% and 14.02%,respectively,and the cumulative contributory ratio was 80.33%.The discrimination functions of the four populations were set up,the discrimination accuracy being 88.9%~100.0% for P1 and 86.7%~ 100.0% for P2,the integrative discrimination accuracy being 95.9%.The resource of Lutraria siebaldii was found in good condition with high genetic variation and Lutraria siebaldii had good culture prospects.