云贵高原银星竹鼠的遗传多样性与遗传结构研究

Study on Genetic Diversity and Genetic Structure of Rhizomys pruinosus

作为一类营地下生活的啮齿动物,银星竹鼠Rhizomys pruinosus具有较高的食用价值和药用价值,已成为我国南方地区特种经济动物养殖业的重点发展物种。以核内重组蛋白激活基因1(RAG1)的基因片段为分子标记,采用分子生物学方法,本研究对来自12个采样点的173个银星竹鼠个体进行群体遗传分析,探讨该物种群体遗传多样性和遗传结构。序列多态性分析结果显示,银星竹鼠RAG1基因部分序列848 bp,共检测出多态性位点18个,其中单突变位点3个,简约信息位点15个。遗传多样性分析表明,173份样本共统计出RAG1基因单倍型11个,单倍型多样性为0.712±0.025,核苷酸多样性为0.002 64±0.003 71,显著低于其他啮齿动物。最大似然法、邻接法和贝叶斯法构建的系统发育树显示,银星竹鼠群体分化为3个分支,其谱系地理格局出现明显分化。同时,分子变异分析结果证实,银星竹鼠种群间的遗传变异极显著高于种群内的,说明该物种存在显著的遗传结构和遗传分化水平。上述研究结果综合表明,银星竹鼠群体的遗传多样性水平较低,遗传分化结构较为显著,这可能与该物种的地下生活方式、扩散能力弱、山脉河流阻隔作用、地质气候事件等因素有关。本研究结果将为云贵高原地区物种多样性、生物多样性保护提供科学的参考依据。

As a subterranean fossorial rodent,Rhizomys pruinosus has high edible and medicinal value and has become an important animal species for the development of special economic animal breeding industry in South China. By using molecular biological methods,this research intends to adopt a molecular marker of nuclear recombination activating gene 1 （RAG1） to investigate the population genetics of 173 individuals from 12 sampling sites,as well as the genetic diversity and phylogeographical structure of R. pruinosus. Polymorphism analysis of R. pruinosus RAG1 gene showed that there were 18 polymorphic sites in the total 848 bp,including 3 single mutation sites and 15 parsimony informative sites. The results of genetic diversity analyses discovered that there were 11 haplotypes from 173 individuals＇ estimation. The haplotype diversity and nucleotide diversity were 0.712±0.025 and 0.002 64±0.003 71,respectively,and these were all significantly lower than that from the estimates of other rodents. The phylogenetic trees constructed by the methods of Maximum Likelihood,Neighbor-Joining and the bayesian tree showed that,R. pruinosus groups diverged to three clades,indicating that obvious differentiation happened in the phylogeographical pattern of this species. In addition,the results of molecular variance analyses approved that the genetic variation among the populations of R. pruinosus was extreme significantly higher than that within populations. This suggested that there were significant differentiation of genetic diversity and genetic structure in total groups of this species. These results comprehensively showed that there were low genetic diversity and remarkable genetic structure in R. pruinosus groups,and these were related with the important factors of subterranean life style,weak distribution ability,mountain river barrier and geological events. These findings will provide a scientific basis for the species diversity and biodiversity protection in the Yunnan-Guizhou Plateau.