斑节对虾养殖群体遗传多样性的同工酶和RAPD分析

采用聚丙烯酰胺凝胶电泳（PAGE）和RAPD方法对厦门养殖斑节对虾（Penaeus monodon Fabricius）群体的遗传多样性进行分析。9种同工酶共检测到21个座位，其中多态座位13个，多态座位比例为61．90％，预期杂合度0．151，观察杂合度0．120，Hardy—Weinberg遗传偏离指数（d）为-0．208，存在杂合子缺失。经x^2拟合度检验，多数座位偏离Hardy—Weinberg平衡，表明群体未达到随机交配。14个10bp引物共获得了83个标记，单个引物获得的标记数为2～11个，平均每个引物扩增出5．93个座位，其中多态标记数68个，多态位点比例为81．93％，杂合度为0．246，基因多样性为0．260，Shannon’S信息指数为0．397。两种方法均表明该斑节对虾养殖群体的遗传多样性水平较高，但可能已有近交衰退发生。

Genetic diversity of reared Penaeus monodon stock revealed by isozyme and RAPD

Isozyme and RAPD methods were used to detect the genetic diversity of cultured Penaeus monodon obtained from Haichuang in Xiamen.All 40 individuals used were the offspring of wild broodstock imported from the coast waters near Sibu,Malaysia.Among the 21 loci in 9 isozymes examined,13 were polymorphic.Mean proportion of polymorphic loci was 61.90% and the observed heterozygosity was 0.120.The expected heterozygosity was 0.151.The genetic deviation index(d value) was 0.208.The Chi-Square test showed that all polymorphic loci except Mdh-2 and Me-2 were not in Hardy-Weinberg equilibrium and existed heterozygote deficiency.Using 14 decamer random primers,83 RAPD sites were detected,of which 68 were polymorphic(81.93%).The average heterozygosity was 0.246,and gene diversity was 0.260.Shannon's information index was 0.397.Compared with isozyme method,RAPD can provide more informative sites and reveal higher genetic diversity.All these results show that the cultured population of Penaeus monodon in Xiamen has a relatively high genetic diversity,but inbreeding may have occurred.