中华鳖培育新品种群体遗传多样性的比较研究

Analysis and Comparison of Genetic Diversity in the New Cultured Varieties of Pelodiscus sinensis

中华鳖日本品系和清溪乌鳖是我国培育的中华鳖类水产动物新品种,品系间亲缘关系及其与国内常见的太湖群体、台湾群体的亲缘关系如何,是决定该新品种进一步选育和开展杂交育种的关键,因此本研究采用RAPD技术对上述4个群体的多态性进行分析。结果表明:在4个种群内共检测出110个RAPD多态位点,不同中华鳖种群内的遗传相似度由高到低依次为中华鳖日本品系(0.846 9)>台湾种群(0.842 9)>清溪乌鳖种群(0.831 7)>太湖种群(0.825 4),太湖种群和清溪乌鳖种群之间的遗传距离最大(0.137 5),台湾种群和清溪乌鳖种群之间的遗传距离最小(0.070 7)。中华鳖总基因多样性为0.236 8,种群内基因多样性为0.1699,表明中华鳖大部分遗传变异(71.75%)存在于种群内,种群间的遗传分化系数为0.282 7。UPGMA聚类分析表明太湖种群与中华鳖日本品系种群为一支,台湾种群与清溪乌鳖种群则聚为另一支,然后这两支再聚在一起。因此要加强对中华鳖种质资源的科学管理和保护,以避免遗传多样性下降。

Pelodiscus sinensis Japanese population and Qingxiwubie are the two new varieties of soft-shell turtle.It is very importance to master the genetic relationship in Pelodiscus sinensis for further breeding and cross breeding,the genetic diversity in the new varieties of Pelodiscus sinensis were studied using random amplified polymorphic DNA（RAPD） technique to compare with the usual populations of Taihu and Taiwan.A total of 162 bands,including 110 polymorphic ones were detected from the four populations by using 23 random primers.The results showed that the level of genetic diversity was high in Japanese population,and the average genetic similarity index within each population ranked as Japanese population（0.846 9）Taiwan population（0.842 9）Qingxiwubie population（0.831 7）Taihu population（0.825 4）.The maximal genetic distance occurred between Taihu and Qingxiwubie populations,while the minimum occurred between Taiwan and Qingxiwubie populations.The total genetic diversity of Pelodiscus sinensis was 0.236 8 and the intra-population genetic diversity was 0.169 9,which suggest that 71.75% of the genetic variation existed within the populations.The genetic differentiation coefficient was 0.282 7,indicating that there was a certain level of population differentiation.With the methods of UPGMA and NJ on the basis of genetic distances,the results showed that the four populations were clustered into two groups： one with Taihu and Japanese populations,and the other with Qingxiwubie and Taiwan populations.Further appropriate measurements must be taken to protect the germplasm of Pelodiscus sinensis from the reduction of genetic diversity.