甘肃境内6个牦牛群体mtDNAD-环序列遗传多样性与聚类分析

Genetic Diversity and Cluster Analysis of Six Yak Populations in Gansu Province Using Mitochondrial D-loop Sequence

利用线粒体DNA分子标记研究了甘肃境内6个牦牛群体的遗传多样性,并进行了聚类和网络关系分析。结果表明：甘肃境内6个牦牛群体240个个体的mtDNA D-loop全序列长度变异为891～895 bp,（G＋C）含量为38.80%,（A＋T）含量为61.20%,说明甘肃境内6个牦牛群体mtDNA D-loop区富含A和T。6个牦牛群体240个体mtDNA D-loop序列共发现60个变异位点,变异主要集中在200～400 bp之间,说明该区域为牦牛mtDNA D-loop区的高变区。240个牦牛mtDNA D-loop序列共发现41种单倍型,在玛曲牦牛和碌曲牦牛群体发现的单倍型数最多,均为21个,其次为夏河牦牛群体（18个）,在天祝白牦牛群体发现的单倍型数最少（11个）。单倍型多样度和平均核苷酸差异数（k）分析表明,来自于甘南州的3个牦牛群体的遗传多样性最丰富,而天祝白牦牛群体最低。41个单倍型序列构建的系统发生树和网络关系分析表明,甘肃境内6个牦牛群体可能具有2个母系起源。

The analysis of genetic diversity,cluster and network relationship were carried out on mtDNA D-loop sequence of 6 yak populations in Gansu province.The results showed that： The length variation of complete mtDNA D-loop sequence was from 891 to 895 base pairs; the（ G ＋ C） content was 38.80%,the（ A ＋ T） content was61.20%,which showed that mtDNA D-loop region was rich in A and T.There were 60 variable sites were found in mtDNA D-loop sequence in 6 yak populations.The variations were mainly concentrated in the range of 200 to 400base pairs,indicating that the region is highly variable region of yak mtDNA D-loop region.Forty one haplotypes were found in 240 yak Individuals,and the number of haplotype found in Maqu yak and Luqu yak populations were the most,which was 21,and that followed by Xiahe yak populations（ 18）.The minimum number of haplotypes（ 11） was found in Tianzhu white yak.Haplotype diversity and average number of nucleotide differences（ k） analysis showed that the most abundant genetic diversity of 3 yak populations in Gannan,but Tianzhu White Yak population was the lowest.Forty one haplotypes constructed phylogenetic trees and networks relationship analysis showed Gansu 6 yak populations may have two maternal origin.