脊尾白虾(Exopalaemon carinicauda)回交家系遗传变异的微卫星分析

Microsatellite Marker Analysis on Genetic Variation of the Ridgetail White Prawn Exopalaemon carinicauda Backcross Populations

为解析脊尾白虾(Exopalaemon carinicauda)回交家系的遗传变异规律,本研究利用自行开发的25个微卫星标记对本实验室构建的A、B、C 3个回交家系的遗传结构特征进行了分析。结果显示,回交家系A、B、C的平均等位基因数(Na)分别为2.21、2.18、2.09,观测杂合度(Ho)分别为0.3805、0.3703、0.2489,期望杂合度(He)分别为0.3629、0.3998、0.2503,多态信息含量(PIC)分别为0.3257、0.3391、0.2585,相较于野生群体与杂交家系已有了大幅度的降低,属中度或低度多态。回交家系A、B、C在25个位点共得到62个等位基因,其中,A家系56个,B家系54个,C家系51个,3个回交家系共同存在的等位基因为39个,6个位点在回交家系中已经纯合(其中,ECL10在A、B、C中都已纯合),计算得出3个回交家系的纯合率分别达到了53.86%、56.53%、63.33%。由此可见,回交家系的基因纯化速率较快,适用于脊尾白虾重要经济性状的遗传解析和优良种质的选育。

In order to analyze genetic effect of the ridgetail white prawn （Exopalaemon carinicauda） backcross families, 25 microsatellite loci were selected to detect the genetic characteristics of three backcross family A, B, C, generated by our laboratory. The results showed that among A, B and C families, the average number of alleles （Na） were 2.21, 2.18 and 2.09, the observed heterozygosity （Ho） were 0.3805, 0.3703 and 0.2489, the expected heterozygosity （He） were 0.3629, 0.3998 and 0.2503 and the polymorphism information content （PIC） were 0.3257, 0.3391 and 0.2585 respectively. Compared to the wild and hybrid population, the genetic diversities of the backcross families were greatly reduced which belonged to moderate or low polymorphism. 62 alleles were obtained in the three backcross families in total using 25 loci. Specifically, 56, 54 and 51 alleles were obtained in A, B and C backcross families, respectively. In addition, there were 39 common alleles in the three backcross families. Six loci have homozygosity in all backcross families （ECL10 in A, B and C families）. The average homozygous rate was 53.86%, 56.53% and 63.33% respectively, which showed that the purification rate of gene was rapid and the backcross is suitable for selective breeding in E. carinicauda.