亲本数目对鲍养殖群体AFLP标记位点及其遗传结构的影响

为了探讨不同的交配亲本数对鲍养殖群体遗传结构的影响,实验中对两个皱纹盘鲍自交群体SS(亲本数少)和LS(亲本数多)及两个皱纹盘鲍(♀)×日本盘鲍(♂)的杂交群体SH(亲本数少)和LH(亲本数多)进行了位点频率和遗传结构的AFLP标记分析。研究表明,自交组中亲本数少的SS群体的总位点数少于LS群体,后者的一些低频位点在前者中丢失,同时群体的位点频率发生漂移,SS的低频位点数目减少而高频位点略有增加。另外统计了各群体的相似指数和杂合度,发现SS群体的相似指数低于LS,而杂合度高于LS群体。在杂交组两群体(SH,LH)中位点数目频率、相似指数和杂合度变化趋势与两自交群体相似。两组结果均表明群体的亲本数减少会引起一些低频位点丢失及位点频率发生漂移,同时亲本数过少会导致群体的杂合度暂时升高。

The influence of parental stock size on the genetic structure of Haliotis discus

In order to reveal the influence of stock size on the genetic structure of f ilial populations, two groups of Haliotis discus hannai ( SS with small number of parents, LS with large number of parents) were analyzed using AFLP( amplif ied fragment length polymorphism) markers. It was found the total number of loci in SS was less than that in LS and some rare loci of LS were lost in SS, Furthermore, the number of low-frequency loci increased, and high-frequency loci slightly decreased in SS compared w ith LS. The similarity was lower and heterozygosity was higher in SS than in LS. In order to prove above results, another two groups ( SH, LH) were also analyzed, which were hybrids of H . discus hannai @ H . discus discus. The trends of loci number, loci f requency, similarity and heterozygote in SH and LH were similar to SS and LS. Both results revealed small parental stock size could result in the loss of low-frequency loci and cause low-frequency loci to drift to highf requency loci, and extremely small stock size could result in temporal increase of heterozygosity.