作 者：
郭娇;钟金城;姬秋梅;信金伟;张成福;柴志欣
单 位：
西藏自治区农牧科学院畜牧兽医研究所;西南民族大学
关键词：
西藏牦牛;mtDNA COⅡ;遗传多样性
摘 要：
为了探讨西藏牦牛的遗传多样性和类群间的系统进化关系以及为西藏牦牛资源的合理保护和利用提供理论依据。对17个西藏牦牛类群170个个体的mtDNA COⅡ全序列进行测序,用MEGA5.0、DNASP5.0等软件分析核苷酸组成、单倍型多样性和核苷酸多样性。通过Kimura-2-Parameter双参数模型和邻近法(NJ)构建系统进化树等方法分析不同牦牛类群的亲缘关系和分类。结果表明:西藏17个牦牛类群的mtDNA COⅡ全序列长度均为684bp,无内含子,共编码227个氨基酸。T、C、A和G 4种核苷酸平均比例分别为28.5%(27.3%~28.8%)、22.7%(22.1%~23.8%)、34.3%(34.1%~34.6%)和14.5%(14.3%~14.6%);G+C平均含量为37.2%,A+T平均含量为62.8%,存在明显的碱基偏倚性。17个西藏牦牛类群的mtDNA COⅡ共有10种单倍型,单倍型多样性值为0~0.844,平均单倍型多样性和核苷酸多样性值分别为0.551、0.008 57,表明西藏牦牛具有较丰富的遗传多样性。西藏牦牛细胞色素c氧化酶亚基Ⅱ中亮氨酸平均含量最多(14.97%),半胱氨酸的平均含量最少(0.88%)。碱性氨基酸、酸性氨基酸的含量分别为8.36%、11%;亲水性氨基酸、疏水性氨基酸分别为50.22%、49.77%。从mtDNA COⅡ来看,西藏17个牦牛类群可分为4大类,即错那牦牛(CN)、仲巴牦牛(ZB)、嘉黎(JL)牦牛、斯布牦牛(SB)、江达牦牛(JD)、工布江达牦牛(GB)、丁青牦牛(DQ)、康布牦牛(KB)、日多牦牛(RD)、巴青牦牛(BQ)为一类,桑日牦牛(SR)、聂荣牦牛(NR)、隆子牦牛(LZ)、帕里牦牛(PL)、申扎牦牛(SZ)为一类,桑桑(SS)牦牛和类乌齐(LWQ)牦牛单独各成一类。
译 名：
Sequence Analysis of mtDNA COⅡof Tibetan Yaks
作 者：
GUO Jiao;ZHONG Jincheng;JI Qiumei;XIN Jinwei;ZHANG Chengfu;CHAI Zhixin;Key Laboratory of Animal Genetics and Breeding of State Ethnic Affairs Commission and Ministry of Education,Southwest University for Nationalities;Institute of Animal Science and Veterinary,Tibet Academy of Agricultural and Animal Husbandry Sciences;
关键词：
Tibet Yak;;mtDNA COⅡ;;Genetic diversity
摘 要：
In order to explore the genetic diversity and the phylogenetic relationships among Tibetan yak groups,and provide theoretical basis for rational protection and utilization of Tibet yak resources, mtDNA COⅡgene of 170individuals from 17Tibetan yak populations were sequenced,and the nucleotide components,haplotype diversities and nucleotide diversities were analyzed with MEGA5.0, DNASP5.0and other softwares.The genetic diversities,phylogenies and classifications of different groups of yak were analyzed by the Kimura-2-Parameter model and NJ phylogenetic tree.The resultsshowed:①the sequence length of the mtDNA COⅡfrom Tibetan yak groups is 684bp,without intron,encoding 227amino acids.The average ratios of 4kinds(T,C,A,G)of nucleotides are 28.5%(27.3%-28.8%),22.7%(22.1%-23.8%),34.3%(34.1%-34.6%)and 14.5%(14.3%-14.6%)respectively;the average content of G+C is 37.2% and the average content of A+T is 62.8%,existing obvious base bias.②10haplotypes of mtDNA COⅡ were detected among the 17 Tibetan yak groups,and the haplotype diversity values changed between 0-0.844,the average haplotype diversity and the nucleotide diversity values was 0.551and 0.008 57,which indicated a high genetic diversity in the Tibetan yaks.③The average content of leucine in the Tibetan yak cytochrome C oxidase subunitⅡis the highest(14.97%),the average content of cysteine is the lowest(0.88%). Contents of basic amino acids and acidic amino acids are 8.36% and 11% respectively.Hydrophilic amino acid and hydrophobic amino acids are 50.22%and 49.77%respectively.④Based on the phylogenetic analysis of mtDNA COⅡ,17groups of Tibetan yaks can be divided into 4categories.Cuona yak(CN),Zhongba yak(ZB),JiaLi yak(JL),Sibu yak(SB),Jiangda yak(JD),Gongbujiangda yak(GB),Dingqing yak(DQ),Kangbu yak(KB),Riduo yak(RD)and Baqing yak(BQ)are included into the first category;Sangri yak(SR),Nierong yak(NR),Longzi yak(LZ),Pali yak(PL)and Shenzha yak(SZ)are clustered into second category;Sangsang yak(SS)is third category and LeiWuqi yak(LWQ)is fourth category.
