团头鲂连续三代减数雌核发育群体遗传变异的微卫星分析

Analysis of genetic homozygosity and diversity of three successive generations of meio-gynogenetic population in Megalobrama amblycephala using microsatellite markers

以普通团头鲂(Megalobrama amblycephala)选育系群体为对照组,利用17个多态性微卫星标记比较分析了团头鲂人工减数雌核发育一代群体(meio-G1)、二代群体(meio-G2)和三代群体(meio-G3)的遗传结构及其基因座位的纯合度,探讨了连续多代诱导减数分裂雌核发育对团头鲂基因纯化的效果。结果表明:17个微卫星座位在对照组、meio-G1、meio-G2和meio-G3中,分别扩增到102、77、45、27个等位基因,平均等位基因数分别为6.0、4.53、2.65、1.59,平均观测杂合度(Ho)分别为0.840 8、0.326 8、0.098 3、0.018 5。meio-G1、meio-G2和meio-G3的平均纯合度分别为0.673 2、0.901 7和0.981 5,三个群体内个体间的平均遗传相似度分别为0.952 0、0.972 5和0.984 5,远高于对照组(平均纯合度0.159 2,平均遗传相似度0.930 6);其中meio-G3群体有12个位点(70.6%)已经完全纯合固定,并与对照组产生较明显的遗传分化;表明连续多代人工诱导减数雌核发育可大大加速团头鲂大多数基因位点的纯合,是快速建立高纯品系的有效手段。

In this study, genetic structure of meiotic gynogenetic populations meio-G1 （the first generation）, meio-G2 （the second generation）, meio-G3 （the third generation） and the control group （ ＂Pujiang No. 1 ＂ genetically selected strains Fs ） of Megalobrama amblycephala was analysed using seventeen microsatellite markers, and the degrees of homozygosity between them were compared. And the efficiency to pure gene for successive artificial meiotic gynogenesis in M. amblycephala was assessed. The results showed that： the numbers of alleles detected were 102, 77, 45 and 27 in the control group, meio-Gl, meio-G2 and meio-G3 , respectively. For the four populations studied, the average numbers of alleles （A） were 6. 0, 4. 53, 2. 65 and 1.59 ; the value of average observed heterozygosity （14o） were 0. 8408, 0. 3268, 0. 0983 and 0. 0185. The average homozygosity among the seventeen analyzed loci were 0. 6732, 0. 9017 and 0. 9815 in meio-G1 , meio-G2 and meio-G3 , respectively, which were much higher than that in the control group （0. 1592 for the av- erage homozygosity）. The average similarity coefficient between individuals within meio-GI , meio-G2 and meio-Gz were 0. 9520, 0. 9725 and 0. 9845, respectively, which were also higher than that in the control group （ 0. 9306 for the average similarity index between individuals）. Value of genetic distance showed significant genetic differentiation between the population of meio-G3 and the control group. Besides, twelve out of seventeen analyzed loci were fixed in meio-G3, show- ing that the homozygosity of most genes can be accelerated by inducing meiotic gynogenesis in M. amblycephala.