罗非鱼3个养殖群体的遗传多样性及特异性AFLP标记研究

对不同来源的养殖群体进行种质鉴定，探索在种苗阶段即区分新吉富罗非鱼（New GIFT strain Oreochromis niloticus）、吉诺玛罗非鱼（GenoMar strain O．niloticus）和奥杂罗非鱼（0．niloticus♀×O．aureus♂）3个养殖群体具有重要的意义。笔者选取了5对AFLP（amplified fragment length polymorphism）引物组合对3个罗非鱼养殖群体共60尾个体进行比较分析，引物组合E—ACA／M—CAT表现出较好的区分能力，有7条标记的分布在群体间表现出“有和无”的差别，引物组合E—ACA／M—CAG的扩增图谱中有2条带表现出“有和无”的差别。遗传多样性方面，平均基因多样性在新吉富罗非鱼和吉诺玛罗非鱼分别为0．1605和0．1595，而在奥尼罗非鱼为0．2214，多态位点百分数和Shannnon多样性指数也表现出相近的变化趋势。分析表明新吉富罗非鱼群体在遗传上已较为稳定，吉诺玛罗非鱼遗传多样性偏低。

Genetic diversity and specific AFLP bands in three cultured tilapia strains

New Gift tilapia, GenoMar tilapia, and the hybrid tilapia of Oreochromis niloticus ♀ × O. aureus ♂ were three major cultured tilapia lines in south China. Identifying these lines was important especially at fry stage. Using amplified fragment length polymorphism （AFLP） technique, we analyzed a total of 60 samples with five primer pairs. Out of 245 AFLP bands, 53.02% were polymorphic. Seven bands from primer pair E-ACA/M-CAT and two bands from E-ACA/M-CAG were found to be specific and could be used to distinguish the three cultured tilapia lines. As for genetic diversity of the three tilapia lines, gene diversity index of New Gift tilapia, GenoMar tilapia, and the hybrid were 0. 1605, 0. 1595, and 0. 2214, respectively. Percent of polymorphic bands and Shannon index presented the similar trend in gene diversity index in these three lines, suggesting that New Gift tilapia was genetically stable, gene diersity index of GenoMar tilapia was a little small.