【摘要】 采用微卫星位点对凡纳滨对虾的海南群体(进口亲虾繁育的第1世代:G1)、山东和饶平群体(G2)、湛江2和湛江3群体(G3)、湛江1和上海群体(G4)共4个世代7个养殖群体的遗传多样性进行了分析。从21对微卫星引物中筛选出12对有效扩增引物,对7个群体共280个个体进行扩增,得到10个多态位点,共获得等位基因数63个。各位点的等位基因数在2—15个之间,各群体的平均等位基因数在4.70—5.80之间。平均观测(期望)杂合度在0.36—0.43(0.53—0.65)之间。杂合子偏离指数(D)为负值,表明存在杂合子缺失现象。对7个群体、10个多态位点进行Hardy-Weinberng平衡检测,共有54个偏离平衡。对7个群体间的遗传分化水平进行检测,得到近交系数FIS在9个多态位点均为正值,两两群体间的固定指数FST值在0.149—0.375之间。FST显著性检验表明,各群体之间的遗传分化极显著(P<0.01)。分子方差分析结果显示,大部分遗传变异(72.17%)来自于群体内,来自于群体间的遗传变异(27.83%)较小。凡纳滨对虾不同世代间遗传变异大,随着繁育世代的增加,遗传多样性降低。更多还原

【Abstract】 The genetic diversity of seven cultured Pacific white shrimp Litopenaeus vannamei stocks of four generations in China was investigated using microsatellite DNA.Twelve pairs of primers were screened out from 21 pairs based on effective amplification.Using the 12 microsatellite loci,ten polymorphic loci were obtained and the percentage of polymorphic loci was 83.33%.At the ten polymorphic loci,the total allele number was 63.Average allele number varied from 2 to 15 for each locus,and from 4.70 to 5.80 for each stock.The mean observed(expected) heterozygosity varied from 0.36(0.53) to 0.43(0.65).The mean value of D(heterozygote deficiency of excess) was negative,indicating an overall deficit of heterozygotes for the seven cultured stocks.54 out of 70 cases(7 stock 10 loci) were detected for significant deviation from Hardy-Weinberg equilibrium.FIS values was positive at nine loci.Pairwise FST values ranged from 0.149 to 0.375 and all pairs of stocks are significantly differentiated.AMOVA indicated that the genetic variation among stocks(27.83%) is lower than that within stocks(72.17%).Genetic difference between generations was obvious,and showed a tendency of decrease from generation to generation.更多还原