日本囊对虾野生群体杂合性的研究

Heterozygosity in the Nine Populations of Wild Marsupenaeus japonicus

运用聚丙烯酰胺凝胶电泳技术研究了日本囊对虾9个野生群体10种等位酶的杂合子缺失及过量状况.在所研究的22个位点中有5个位点(Sod-1、Est-1、Est-2、Amy-3、Mdh-1)是多态位点.汕头群体的Est-2,北海群体的Mdh-1和Sod-1,湄洲群体的Mdh-1,连江群体的Sod-1和漳浦群体的Mdh-1位点符合H-W平衡标准(P>0.05);其余的多态位点均显著或极其显著地偏离H-W平衡标准(0.01<P<0.05或P<0.01).另外,日本囊对虾9个群体的Est-2位点均表现出杂合子缺失(F>0);Amy-3和Est-1(除了泉州群体的Est-1)位点均表现出杂合子过量(F<0).研究表明日本囊对虾野生资源杂合性状况较好.

Heterozygosity was investigated using an assay of vertical slab polyacrylamide gel electrophoresis in nine Marsupenaeus japonicus populations. Ten enzymes presumably encoded by 22 allozyme loci were scored in M. japonicus. 5 loci were polymorphie. They were Sod-1, Est-1, Est-2, Amy-3, Mdh-1. Results also showed that the genotype distribution observed at Est-2 in Shantou, Mdh-1 and Sod-1 in Beihai, Mdh-1 in Meizhou, Sod-1 in Lianjiang, Mdh-1 in Zhangpu was found to be in agreement with that expected from the Hardy-Weinberg equilibrium （P 〉 0. 05 ） . But other polymorphic loci in the nine populations were found to depart clearly from the Hardy-Weinberg equilibrium （0. 01 〈 P 〈 0. 05 or P 〈 0. 01 ） . There was heterozygote deficiency in Est-2 （F 〉 0） , and heterozygote excess in loci Aray-3, Est-1 in the nine populations （except locus Est-1 in the Quanzhou population） （F 〈 0） . It indicated that the heterozygous situation of M. japonicus was good. Main causes of heterozygote deficiency, resulting in disappearance of allele, lower genetic diversity and lower environmental adaptation ability, were natural selection, inbreeding effects, presence of null allele and the Wahland effect.