长江口泥螺群体遗传多样性的AFLP分析

Amplified fragment length polymorphism analysis of the genetic diversity of Bullacta exarata in the Yangtze estuary

本研究应用AFLP分子标记技术,对我国长江口泥螺的4个群体（江苏启东,崇明东滩,九段沙湿地国家自然保护区和上海南汇）进行了遗传多样性分析。4对AFLP引物扩增得到577个位点,启东、崇明、九段沙和南汇群体的多态率分别为78.2%、56.0%、58.4%和57.9%。群体总基因多样性为0.2218,显示出较高的遗传多样性水平,且96%以上的遗传变异存在于群体内,群体间的遗传分化极微小（0.0000~0.0404）。群体间Nei’s遗传距离为0.0000~0.0124,主要存在于江苏启东群体和其他3个群体之间。利用STRUCTURE分析群体隐性遗传结构,结果表明长江口泥螺群体有3种遗传来源,同时群体之间有强大的基因流。泥螺较强的扩散能力和海洋开放的环境可能是造成泥螺群体遗传同质性较高的主要原因。

In this study, the genetic diversity ofBullacta exarata from four populations （Qidong, Chongming Dongtan, Jiuduansha, and Nanhui） in the Yangtze estuary were investigated based on amplified fragment length polymorphism （AFLP） profiles. The four AFLP primer combinations produced 577 AFLP loci and the percent loci polymorphic values for QD, CM, JD, and NH were 78.2%, 56.0%, 58.4%, and 57.9%, respectively. The total gene diversity index was 0.2218, indicating a high level of genetic diversity and over 96% of the genetic variation was because of individuals within populations. Genetic differentiations among populations were very low （0.0000–0.0404） and the Nei’s genetic distance among four populations varied from 0.0000 to 0.0124. In addition, structure analysis indicated thatB. exarata popula-tions originated from three genetic groups and strong gene flow existed among populations. The ability ofB. exarata to disperse in the open sea could be the cause of the slight genetic variation in the studied areas.