| [Objective] Explore the maternal genetic diversity, population structure and genetic background of the Golmud yak in Qinghai Province at molecular level. [Method] The present study analyzed the 618 bp mtDNA D-loop sequences of 49 Golmud yaks and identified the number of haplotypes and corresponding polymorphic sites. The indexes of haplotype diversity and nucleotide diversity were also calculated using DnaSP 5.10.01、Arlequin 3.11 and MEGA 5.05 software. [Results] After excluding one InDel site, 45 polymorphic sites including ten single polymorphic sites and 35 parsimony information sites were detected totally. According to the nucleotide variations among sequences, 18 haplotypes were identified, among which H4 haplotype was dominant. The nucleotide diversity and haplotype diversity of Golmud yak were 0.015?0.008 and 0.911?0.022, respectively. Compared with wild yak and other domestic yak breeds (i.e. Datong, Tianzhu and Jinchuan), Golmud yak has higher values of haplotype diversity and nucleotide diversity, indicating rich maternal genetic diversity. Taking Bison bison（GenBank No.：EU177871）as outgroup, phylogenetic tree constructed by NJ method showed that 18 haplotypes identified in Golmud yak were distributed in A, B, C, D and G haplogroups. These haplotypes/haplogroups could be clustered into three maternal lineages, which indicated that Golmud yak had three maternal origins. [Conclusion] Golmud yak population owned rich maternal genetic diversity, which is composed of five haplogroups (A, B, C, D and G) individuals distributed in three lineages with three maternal origins. |