Abstract
Yak (Bos grunniens ) is a unique livestock animal originating from
the Qinghai-Tibet Plateau in China. In the current study, we
investigated the maternal genetic diversity, differentiation and
phylogeny of wild yak population and
four domestic yak breeds (Qinghai-Gaoyuan, Huanhu, Xueduo, and Yushu) in
Qinghai, China by analyzing 166 mitochondrial cytochrome b
(Cytb ) gene sequence
variations. Our results indicated that the haplotype and nucleotide
diversities of wild yak were 0.883±0.044 and 0.004±0.002, while the
total haplotype and nucleotide diversities of four Qinghai domestic yak
breeds were 0.646±0.040 and 0.003±0.001, respectively. Among the four
Qinghai domestic yak breeds, the haplotype diversity was found to be
highest in Yushu yak breed (Hd = 0.770±0.053), while the lowest was
recorded in Huanhu yak breed (Hd = 0.501±0.088). Estimates ofF ST values showed a moderate genetic
differentiation between wild yak and Huanhu yak
(F ST = 0.058) as well as that between
Huanhu yak and Yushu yak breeds
(F ST = 0.052), but a weak genetic differentiation
was observed between the other yak breeds/populations
(-0.021<FST <0.037). Additionally, the
clustering analysis based on RST values showed
that Xueduo yak and Huanhu yak were clustered into one group, and each
of the other three yak breeds/populations was separated into one group,
respectively. Overall, the clustering relationship between wild yak and
Yushu yak was closer. Maternal phylogenetic analysis showed that wild
yak and four local yak breeds/populations in Qinghai represented in
three maternal lineages (Mt-Ⅰ, Mt-Ⅱ, and Mt-Ⅲ), indicating three
maternal origins in yak. Our study would provide valuable information
for the conservation and utilization of wild yak and Qinghai domestic
yak breeds.