作 者：
李莉好;喻达辉;黄桂菊;叶卫;杜博;符云;童馨;郭奕惠
单 位：
中国水产科学研究院南海水产研究所;广东省国家级罗非鱼良种场
关键词：
杂交罗非鱼;遗传多样性;遗传分化;微卫星DNA
摘 要：
用7对微卫星引物检测了尼罗罗非鱼(Oreochromis niloticus)和奥利亚罗非鱼(O.aureus)群体及其正、反交群体共128个个体的遗传多样性。共检测到38个等位基因,尼罗罗非鱼、奥利亚罗非鱼、正交群体和反交群体的平均等位基因数分别为4.0、1.4、5.3和2.7,平均PIC值分别为0.557、0.099、0.590和0.497,平均观测杂合度分别为0.505、0.071、0.826和0.883,平均期望杂合度分别为0.622、0.117、0.684和0.598,杂合子偏离指数(D)分别为-0.146、-0.241、0.215和0.522。结果表明,正交群体的遗传多样性比两个亲本群体都高,反交群体介于两个亲本群体之间;正交群体的观测杂合度和期望杂合度也高于两亲本群体,反交群体的期望杂合度介于两者之间,但实际观测杂合度却最高;两亲本群体存在一定的杂合子缺失,而杂交群体则存在杂合子增加的现象,尤其是反交群体的观测杂合度大量增加。卡方检验表明,正交群体偏离Hardy-Weinberg平衡的位点较少(3个位点),而其他3个群体大部分位点均偏离平衡,存在遗传漂变现象。4个养殖群体间遗传分化具有显著性(FST为0.081~0.610,P<0.01)。UPGMA系统树显示,正交种与尼罗罗非鱼的亲缘关系较近。表明正交群体受亲本群体的影响最大,其生长优势除了性别因素外,遗传因素可能也具有重要作用。
译 名：
Genetic diversity of Oreochromis niloticus,O. aureus and their reciprocally-crossed hybrid stocks
作 者：
LI Li-hao1,2,YU Da-hui1,HUANG Gui-ju1,YE Wei3,DU Bo1,4,FU Yun3,TONG Xin1,4,GUO Yi-hui1 (1.South China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Guangzhou 510300,China;2.Shanghai Ocean University,Shanghai 200090,China;3.Guangdong National Elite Tilapia Farm,Guangzhou 511453,China;4.Fisheries College,Huazhong Agricultural University,Wuhan 430070,China)
关键词：
hybrid tilapia;genetic diversity;genetic differentiation;microsatellite DNA
摘 要：
Hybrid tilapias produced by cross of Oreochromis niloticus and O. aureus grow much faster than parental tilapias in culture pond due to mono-sex and thus have become the favorites of fish farmers. Yet genetic variation of hybrid tilapias is less investigated and the mechanism of fast growth is not completely understood. Therefore genetic diversity of O. niloticus,O. aureus,forward hybrid O. niloticus♀ × O. aureus♂ and reverse hybrid O. niloticus♂ × O. aureus♀ stocks was investigated in this study using seven microsatellite loci. Thirty- eight alleles in total were detected from 128 individuals among the four stocks. The average numbers of alleles for the four tilapias stocks were 4,1.4,5.3 and 2.7,respectively. The mean levels of observed heterozygosity were 0.505,0.071,0.826 and 0.883,respectively. The average levels of expected heterozygosity were 0.622,0.117,0.684 and 0.598,respectively. The averages of polymorphism information content were 0.557,0.099,0.590 and 0.497, respectively. D values for deviation of heterozygosity were-0.146,-0.241,0.215 and 0.522,respectively. These observations suggested that forward hybrid stock had the highest level of genetic diversity,while O. aureus the lowest,and that O. niloticus and O. aureus exhibit slightly heterozygote deficiency,whereas the two hybrid stocks exhibit heterozygote excess. Chi-square tests showed that most loci in forward hybrid stock (4/7) are in Hardy- Weinberg equilibrium,whereas most loci in the other three stocks deviate,suggesting occurrence of genetic drift possible due to founder effect. Genetic differentiation was significant among the stocks as revealed by random permutation test (pairwise FST 0.081-0.610,P < 0.01). An UPGMA tree demonstrated that forward hybrid stock is genetically near to Nile tilapia stock. These observations suggested that genetic diversity of forward hybrid stock gets more contributions from parental stocks than reverse hybrid stock and the growth dominance is not only influenced by sexuality but also possibly by added genetic diversity.
