藏绵羊DQA座位基因的适应性进化研究  

Adaptive Evolution of DQA Loci Genes in Tibetan Sheep(Ovis aries)

作　　者：刘秀[1] 胡江[1] 王继卿[1] 李少斌[1] 李文浩[1] 焦丹[1] 罗玉柱[1] 

机构地区：[1]甘肃农业大学动物科学技术学院/甘肃省草食动物生物技术重点实验室/甘肃省牛羊基因改良工程实验室,兰州730070

出　　处：《农业生物技术学报》2016年第7期1039-1046,共8页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金项目(No.31260546);国家科技支撑计划项目(No.2012BAD13B05);甘肃省创新研究群体计划项目(No.1210RJIA005);甘肃省国际科技合作专项(No.1304WCGA178)

摘　　要：主要组织相容性复合体(major histocompatibility complex,MHC)是脊椎动物重要的功能基因家族之一,其所编码的MHC分子具有维持机体世代适应环境变化的能力和功能,是研究动物适应性进化研究的最佳遗传标记。本研究选择青藏高原的主要畜种资源——藏绵羊(Ovis aries)为研究对象,利用聚合酶链式反应-单链构象多态(polymerase chain reaction-single strand conformation polymorphism,PCRSSCP)技术对甘肃(欧拉,乔科和甘加型)和青海(青海欧拉型和青海高原型)的5个藏绵羊生态群体的DQA座位基因遗传特征进行研究,以期揭示其与藏绵羊高原适应性进化的机制;结果在藏绵羊DQA座位的2个基因中发现了33个等位基因和125个核苷酸变异位点,表明5个生态群体藏绵羊的DQA座位基因均具有丰富的多态性;分析证明平衡选择是维持藏绵羊DQA座位基因多态性的主要机制之一,甘肃和青海5个藏绵羊生态群体DQA座位基因区域之间的变化(among groups)小于同一区域不同群体间的变化(among population with groups),进一步说明藏绵羊DQA座位基因发生了正选择作用和适应性进化。研究结果将为藏绵羊的遗传改良和种质创新提供基础数据。Major histocompatibility complex（MHC）, one of the vital functional gene families in vertebrates,encodes MHC molecule which has the function and ability to maintain the organism adapt to environmental changes from generation to generation, and is the best genetic marker for investigating adaptive evolution in animals. Tibetan sheep（Ovis aries）, the main livestock resources in Qinghai- Tibetan plateau, was chosen as research object, and the genetic characteristics of DQA genes in 5 ecological Tibetan sheep populations from Gansu（Oula, Qiaoke and Ganjia type） and Qinghai（Oula and plateau type） were investigated using polymerase chain reaction- single strand conformation polymorphism（PCR- SSCP） techniques in this study,which aimed to reveal its adaptive evolutionary mechanism in plateau Tibetan sheep. The results showed that33 alleles and 125 SNPs were discovered in 2 genes of Tibetan sheep DQA locus. This indicated that the DQA genes in 5 ecological Tibetan sheep populations exhibited abundant polymorphism. Subsequent analysis demonstrated that balancing selection was one of the mechanisms to maintain the polymorphism of DQAgenes in Tibetan sheep. The changes of DQA genes among groups in 5 ecological Tibetan sheep from Gansu and Qinghai were less than those among population with groups, suggesting that the DQA genes in Tibetan sheep generates positive selection and adaptive evolution. This research results will provide basic data for genetic improvement and germplasm innovation of Tibetan sheep.

关 键 词：DQA基因 适应性进化 平衡选择 藏绵羊 

分 类 号：Q311[生物学—遗传学]