作 者：
夏小婷;马志杰;张成福;蓝贤勇;陈宏;雷初朝
单 位：
西藏自治区农牧科学院畜牧兽医研究所;西北农林科技大学动物科技学院;青海省畜牧兽医科学院
关键词：
西藏牛;Y染色体;USP9Y;mtDNA D-loop;遗传多态性;起源
摘 要：
本研究旨在探究西藏牛的Y染色体与mtDNA D-loop区的遗传多态性和起源。采用PCR扩增和限制性内切酶酶切的方法测定30头西藏牛Y染色体USP9Y基因的多态性;采用PCR扩增和测序技术测定30头西藏牛的mtDNAD-loop区序列,利用生物信息学的方法对西藏牛44条D-loop序列(其中14条从Gen Bank下载)进行遗传多态性分析。对30头西藏牛USP9Y基因的PCR产物进行电泳,共检测到471 bp和552 bp 2个片段,且552 bp片段不能被限制性内切酶Ssp I切开,说明西藏牛具有普通牛Y1和Y2 2种单倍型组,其频率分别为0.067和0.933。通过对44条西藏牛mtDNA D-loop全序列进行比对,发现本研究测定的30条西藏牛mtDNA D-loop全序列中,有8条为牦牛序列,说明西藏牛群体中有牦牛的基因渗入。对36条西藏牛mtDNA D-loop全序列进行分析,共检测到62个变异位点,界定了21个mtDNA单倍型,单倍型多样度为0.956 0,核苷酸多样度为0.006 4,表明西藏牛具有丰富的母系遗传多态性。系统发育树显示,西藏牛具有普通牛和瘤牛混合母系起源,且普通牛的单倍型在西藏牛群体中占绝对优势(95.24%)。西藏牛具有丰富的母系遗传多态性,由2个普通牛父系单倍型组构成,应归于普通牛一类,且群体中存在牦牛和瘤牛的基因渗入现象。
译 名：
Genetic Diversity of Y Chromosome USP9Y Gene and Mitochondrial DNA D-loop Region in Tibetan Cattle
作 者：
XIA Xiao-ting;MA Zhi-jie;ZHANG Cheng-fu;LAN Xian-yong;CHEN Hong;LEI Chu-zhao;College of Animal Science and Technology,Northwest A&F University;Academy of Animal Science and Veterinary Medicine,Qinghai University;Institute of Animal Science,Tibet Academy of Agricultural and Animal Husbandry Sciences;
单 位：
College of Animal Science and Technology,Northwest A&F University%Academy of Animal Science and Veterinary Medicine,Qinghai University%Institute of Animal Science,Tibet Academy of Agricultural and Animal Husbandry Sciences
关键词：
Tibetan cattle;;Y chromosome;;USP9Y;;Mitochondrial DNA D-loop;;Genetic diversity;;Origins
摘 要：
This study is to investigate the genetic diversity and the origins of Y chromosome and mitochondrial DNA D-loop region in Tibetan cattle. Using PCR amplification and restriction enzyme digestion methods to detect the polymorphism of Y chromosome USP9 Y gene of 30 Tibetan cattle; the complete D-loop region sequences of mitochondrial DNA from 30 individuals in Tibetan cattle were determined by PCR amplification and sequencing methods. Bioinformatics method was used to analyze the genetic polymorphism of 44 D-loop sequences in Tibetan cattle(of which 14 sequences of Tibetan were obtained from Gen Bank). 30 individuals of Tibetan cattle were analyzed using a recently discovered USP9 Y marker that could distinguish taurine from zebu more efficiently. The results showed that the USP9 Y sequence-tagged sites of Tibetan cattle were detected two DNA fragments, 471 bp and 552 bp, and the 552 bp DNA fragment can't be digested by Ssp I enzyme, indicating that Tibetan cattle only had Y1 and Y2 haplogroups. The haplogroup frequencies of Y1 and Y2 were 0.067 and 0.933, respectively. To compare with 44 individuals of the complete mitochondrial DNA D-loop region in Tibetan cattle, 8 individuals were proved to belong to yak which detected in this study, indicating the introgression of genes from the yak. 62 mutation sites and 21 haplotypes were found in 36 individuals of complete mitochondrial DNA D-loop sequences of Tibetan cattle. Nucleotide diversity was 0.0064 and haplotype diversity was 0.9560, suggesting an abundant mitochondrial genetic diversity in Tibetan cattle. Phylogenetic analysis showed that the maternal origins of Tibetan cattle were from Bos taurus and Bos indicus, and the taurine haplotypes dominated the Tibetan cattle population(95.24%). Our results demonstrated that Tibetan cattle have rather abundant mitochondrial genetic diversity, consisting of two taurine paternal haplogroups. The Tibetan cattle should be classified as Bos taurus, and our study also revealed a female yak and zebu introgression in Tibetan cattle.
