| [Objective] The maternal genetic diversity, population structure and genetic background of the Tanggulashan yak population in Qinghai Province were explored at molecular level. [Method] The mtDNA D-loop region of 52 Tanggulashan yaks were sequenced with polymorphic sites and bioinformatic analysis for haplotype numbers, haplotype diversity and nucleotide diversity, and phylogenetic analysis. [Results] In the 619 bp D-loop region, 31 polymorphic sites were detected after excluding 2 insertions (deletions), including 5 single polymorphic sites and 26 parsimony information sites. A total of 13 haplotypes were identified based on nucleotide sequence variations with nucleotide diversity of 0.007±0.004 and haplotype diversity of 0.821±0.043. Compared with wild yak and other 18 domestic yak breeds/populations in China, the values of haplotype diversity and nucleotide diversity of Tanggulashan yak population were relatively lower, indicating poor genetic variation and lower level of maternal genetic diversity. The phylogenetic tree constructed by NJ method showed that 13 haplotypes belonging to A, B, C, D and E were clustered into two large maternal lineages (I and II) with lineage I accounted for 77%, indicating that Tanggulashan yak population is composed of two maternal lineages and has two maternal origins. [Conclusion] The Tanggulashan yak population had relatively lower maternal genetic diversity, consisting of two maternal lineages dominated by lineage I, which is speculated to have two maternal origins. |