马氏珠母贝养殖群体早期生长阶段的遗传多样性与有效亲本数量估计

Genetic Diversity and Effective Population Size Estimate in the Stock of Pearl Oyster Pinctada fucata martensii at Early Growth Stages

从大亚湾野生群体选择亲本繁育1个养殖群体,受精第6天、23天与80天分别进行优选,按50%选留比率选留快生长个体,分别在受精后第3天、30天120天取样,利用8对SSR标记分析养殖群体遗传多样性与估计有效亲本数量。结果表明,在3个生长阶段每个位点的平均等位基因数分别为3.750、3.875和3.625,平均观察杂合度分别为0.324 2、0.527 3和0.372 4,平均期望杂合度分别为0.551 1、0.561 3和0.504 8。有效亲本数量的估计分别为38、28和30,3个生长阶段估算的有效亲本数量均比实际所用到的亲本数量少。选优管养措施导致养殖群体的遗传多样性与有效亲本数量降低。

In this paper the effects of selection for faster growth on genetic diversity and effectivepopulation size in the stock of pearl oyster Pinctada fucata martensii is reported. In May of 2012,astock was established by the breeders collected from Daya Bay wild population. The female and malebreeder numbers were 30 and 20,respectively. Selection practices were performed at days 6,23 and 80after fertilization. The selection percentage was 50% at each time. Animals were sampled at days 3,30and 120 after fertilization. Genetic diversity and effective population size were analyzed by using eightSSR primer pairs. The results showed that the average numbers of alleles at each sampling time were3.750,3.875 and 3.625,respectively. The average observed heterozygosities in the stock at eachsampling time were 0.324 2,0.527 3 and 0.372 4,respectively. The average expected heterozygosities inthe stock at each sampling time were 0.551 1,0.561 3 and 0.504 8,respectively. Effective populationsizes at each sampling time were 38,28 and 30,respectively. A decrease in effective population size ateach sampling time relative to the number of breeders used to develop the stock was detected. The present results suggested that selection practices could result in decreases in genetic diversity andeffective population size in the stock of pearl oyster P. fucata martensii.