棕点石斑鱼(♀)与蓝身大斑石斑鱼(♂)及其杂交子代遗传多样性分析

Genetic Diversity Analysis of Epinephelus fuscoguttatus(♀)and E.tukula(♂)Hybrids

本研究利用20对石斑鱼微卫星引物对金虎斑[棕点石斑鱼(Epinephelus fuscoguttatus) (♀)×蓝身大斑石斑鱼(E.tukula)(♂)]及其父母本进行微卫星分析,从分子水平对金虎斑及其双亲的遗传多样性进行研究。结果显示,20个微卫星位点共检测到215个等位基因,平均多态信息含量(PIC)为0.638 6;棕点石斑鱼平均有效等位基因数(Ne)最多(4.367 9),金虎斑次之(3.370 6),蓝身大斑石斑鱼最少(2.412 8);蓝身大斑石斑鱼、棕点石斑鱼和金虎斑3个群体平均观测杂合度(Ho)分别为0.385 5、0.4749和0.473 6,PIC分别为0.491 9、0.645 3和0.555 1;3种石斑鱼群体群内近交系数(Fis)、总群体近交系数(Fit)、遗传分化系数(Fst)和基因流(Nm)平均值分别为0.228 0、0.344 1、0.150 4和1.411 9,群体间分化较大;采用UPGMA法构建的聚类分析图显示,金虎斑与棕点石斑鱼先聚为一类,二者亲缘关系更近。研究表明,金虎斑存在较丰富的遗传多样性表现,在遗传学方面可进行杂交石斑鱼进一步选育及杂种优势研究。

The genetic diversity of Jinhu grouper hybrids(Epinephelus fuscoguttatus♀×E.tukula♂)and their parents were analyzed via microsatellites.The results detected 215 alleles at 20 microsatellite loci,with an average polymorphic information content(PIC)of 0.6386.The highest average effective allele number(Ne)was measured in E.fuscoguttatus(4.3679),followed by the hybrids(3.3706)and E.tukula(2.4128).The average observed heterozygosity values(Ho)were 0.3855(E.tukula),0.4749(E.fuscoguttatus),and 0.4736(hybrids),and the average PIC values were 0.4919,0.6453,and 0.5551,respectively.The three grouper populations were averaged to calculate the inbreeding coefficient(Fis;0.2280),total population inbreeding coefficient(Fit;0.3441),genetic differentiation coefficient(Fst;0.1504),and gene flow(Nm;1.4119),but differentiation among the populations was also observed.Cluster analysis,performed by the unweighted pair group method with arithmetic mean,placed the hybrids and E.fuscoguttatus into one group,indicating a close relationship.Prior studies showed that the Jinhu grouper is genetically diverse,which allowed for selective breeding,hybrid generation,and exploration of the genetic basis of heterosis.