中华绒螯蟹野生群体和不同水系人工选育群体的遗传多样性分析

Genetic Diversity Analysis of Wild and Cultured Population of Eriocheir sinensis from Different Water Systems

中文关键词: 中华绒螯蟹  遗传多样性  遗传分化  微卫星

英文关键词: Eriocheir sinensis  Genetic diversity  Genetic differentiation  Microsatellite

中文摘要:

      本研究利用10个微卫星分子标记分析了中华绒螯蟹(Eriocheir sinensis) 3个不同水系人工选育群体(“长江1号”、“光合1号”和七里海河蟹)和1个海河流域自然群体的遗传多样性和遗传分化水平。结果显示，10个位点在4个群体中的等位基因数(N)为3~17，平均等位基因数为8.5~9.7，平均期望杂合度为0.720~0.745，平均观测杂合度为0.566~0.661，平均多态信息含量为0.687~0.716，近交系数(Fis)范围为–0.080~0.827。在40个群体–位点组合中，有13个群体–位点组合显著偏离哈迪–温伯格平衡(P<0.05)。遗传多样性分析结果显示，与海河自然群体相比，3个人工选育群体遗传多样性水平略有降低，但仍保持在较高水平，具有较大的选育潜力。遗传分化分析结果显示，群体间遗传分化指数(Fst)范围为0.015~0.075，遗传相似度为0.7702~0.9401，遗传距离为0.0617~0.2611。基于Nei’s遗传距离构建了群体UPGMA系统进化树，自然群体和“光合1号”聚为一支，而七里海河蟹群体单独聚为一支。综上所述，4个中华绒螯蟹群体间的遗传分化水平较低，群体遗传多样性较高。本研究将为中华绒螯蟹选育繁育和种质资源利用与管理等提供理论基础。

英文摘要:

      The Chinese mitten crab Eriocheir sinensis is one of the most economically important aquaculture species in China due to its taste and nutritional value. In this study, the genetic status of both wild and cultivated stocks of E. sinensis was assessed using simple sequence repeat (SSR) markers. Ten microsatellite markers reported in previous studies were selected to estimate the level of genetic diversity within one Haihe natural population and three selected artificial populations (Yangtze No.1, Guanghe No.1, and Qilihai crab) and to compare the degree of genetic differentiation among them. Unique PCR products and high levels of polymorphism were observed for all loci. For the four populations of E. sinensis, the number of alleles per locus ranged from 3 to 17, with a mean allele number of 8.5 to 9.7. The mean observed heterozygosities ranged from 0.566 to 0.661, while the mean expected heterozygosities ranged from 0.720 to 0.745. Additionally, the mean polymorphism information content ranged from 0.687 to 0.716. Furthermore, the inbreeding coefficient (Fis) ranged from 0.080 to 0.827, and there were 13 cases that significantly deviated from the Hardy-Weinberg equilibrium (P<0.05) among the 40 population-locus cases (4 populations × 10 loci). The results of the microsatellite survey indicated that the genetic diversity of the three artificially selected populations was slightly lower than that of the natural population, but still maintained at a high level for further breeding. The analysis of genetic differentiation showed that Fst ranged from 0.015 to 0.075, genetic similarity ranged from 0.7702 to 0.9401, and genetic distance ranged from 0.0617 to 0.2611. UPGMA phylogenetic analysis divided these populations into two groups. Natural population and Guanghe No.1 stocks were allocated to the same cluster, and the Qilihai crab was allocated to another cluster. In conclusion, the four populations of E. sinensis possessed high genetic diversity but low to moderate levels of genetic differentiation. The information on the genetic variation and differentiation obtained in this study will provide a theoretical basis for further breeding and utilization of germplasm resources of E. sinensis.