凡纳滨对虾引进群体和养殖群体的PCR-RFLP分析

采用PCR-RFLP方法,对2008年引进的SPF凡纳滨对虾群体(G0)与2006年引进亲虾繁育的两代群体(G1、G2)的遗传结构进行了分析。使用AluI、TaqI、M boI、SpeI、SspI共5种限制性内切酶对线粒体DNA控制区进行单酶切分析,酶切得到的单倍型在2~4个之间,三个群体的复合单倍型类型分别有3个、7个和9个,没有为三个群体所共有的复合单倍型,复合单倍型的分布显示群体间差异显著。三个群体(G0、G1、G2)的核苷酸多样度π值逐渐增加,分别为0.033 3、0.128 6、0.134 9,复合单倍型多样度h分别为0.622 2、0.850 0、0.847 0,说明养殖群体的遗传多样性大于引进群体。聚类分析的结果表明随着养殖世代的增加,养殖群体与引进群体的差异呈增大的趋势。由此推测G0与G1的亲本存在较大的遗传差异,并且在使用引进群体作为亲本的育种过程中可能出现了种质混杂。

PCR-RFLP analysis of imported and cultured stocks of Litopenaeus vannamei

In this study,genetic structures of three populations were analysed,including population G0 imported from abroad in 2008 and two cultured populations(G1 and G2) of filial generations bred from imported primary parents in 2006.Five restriction enzymes(Alu I、Taq I、Mbo I、Spe I、Ssp I) were used in the PCR-RFLP analysis of the mtDNA control region.The number of haplotype was between two and four.There were 3、7 and 9 kinds of composite haplotypes in the three populations respectively.No composite haplotype shared by three populations was detected, and the distribution of the composite haplotypes demonstrated that there was a significant difference.The π value of the three populations(G0、G1、G2)increased gradually, being 0.033 3、0.128 6 and 0.134 9 respectively. Composite haplotype diversity(h) of the three populations were 0.622 2、0.850 0 and 0.847 0 respectively ,which indicated that the cultured stocks had a higher genetic diversity compared with the imported stock. The dendrogram showed that there was an increasing genetic difference between the cultured stocks and imported stock as generation proceeded. Therefore, it was presumed that there be major differences between G0 and the imported primary parents of G1, and population mixing might have happened when the imported population was employed as primary parents in the breeding programme.