吉富罗非鱼不同选育群体的遗传多样性

用微卫星和扩增片段长度多态性(amplified fragment length polymorphism,AFLP)分子标记对海南、广州和青岛吉富品系尼罗罗非鱼的遗传多样性和遗传分化进行了研究。9对微卫星引物和4对AFLP引物的分析结果一致。微卫星分析表明,青岛吉富鱼的平均等位基因数(4.8)、平均观测杂合度(0.528)、平均多态信息含量(0.605)最高,海南吉富鱼的平均等位基因数(4.4)、平均观测杂合度(0.479)、平均多态信息含量(0.549)最低。AFLP分析显示,青岛吉富鱼的多态位点比例(48.4%)和基因多样性(0.245)最高,海南吉富鱼的多态位点比例(36.3%)和基因多样性(0.147)最低。这些表明,青岛吉富鱼的遗传多样性最高,海南吉富鱼最低。遗传分化分析表明,两两群体间遗传分化显著(微卫星FST为0.07~0.11,P<0.01;AFLPFST为0.24~0.29,P<0.01)。AMOVA分析显示,大部分遗传变异(微卫星的分析结果为91.26%;AFLP的为67.6%)来源于群体内个体间,表明吉富鱼选育品系尚具有进一步选育的潜力。

Genetic diversity of selected GIFT strains of Oreochromis niloticus

Genetic diversity and differentiation among three stocks of selected GIFT strains of Oreochromis niloticus was analyzed using microsatellite DNA and AFLP markers.Nine microsatellite loci and four primer pairs of AFLP revealed consistent results.Microsatellite data showed that Qingdao GIFT stock had the highest mean number of alleles(4.8),mean observed heterozygosity(0.528)and mean PIC(0.605),whereas Hainan GIFT the lowest.AFLP analysis demonstrated that Qingdao GIFT had the highest proportion of polymorphic loci(48.4%)and gene diversity within populations(0.245),whereas Hainan GIFT the lowest.These observations indicated that Qingdao GIFT has the highest genetic diversity,whereas Hainan GIFT the lowest.Genetic differentiation among the three GIFT strains was significant as revealed by microsatellite(FST=0.07~0.11,P<0.01)and AFLP(FST =0.24~0.29,P<0.01).AMOVA indicated that the majority of genetic variation(91.26% by microsatellite analysis and 67.6% by AFLP)was attributed to difference of individuals within stocks,suggesting that GIFT strains of O.niloticus has some potential for further selective breeding.