High-altitude adaptation of yak and yak domestication

• 作 者: Liu Jianquan
• 机 构: Sichuan University, Chengdou Sichuan,610065
• 出 处: 2017第四届中国肉牛选育改良与产业发展国际研讨会
• 发表日期: 2017年3期

　　Domestic yaks (Bosgrunniens) provide meat and other necessities for Tibetans living at high altitude on the Qinghai-Tibetan Plateau and in adjacent regions.We compared genome differentiation between yak and the closely related low-altitude cattle.We identified an expansion in yak of gene families related to sensory perception and energy metabolism,as well as an enrichment of protein domains involved in sensing the extracellular environment and hypoxic stress.We also found that positively selected and rapidly evolving genes in the yak lineage to be significantly enriched in functional categories and pathways related to hypoxia and nutrition metabolism.Based on the yak reference genome,we further investigated domestication of yaks through resequencing wild and domestic yaks.We identified signals of selection in 209 genes of domestic yaks,several of which relate to behaviour and tameness.We dated yak domestication to 7,300 years before present (yr BP),most likely by nomadic people,and an estimated six fold increase in yak population size by 3,600 yr BP.These dates coincide with two early human population expansions on the Qinghai-Tibet Plateau during the early-Neolithic age and the late-Holocene,respectively.Our findings add to an understanding of yak domestication and its importance in the early human occupation of the Qinghai-Tibet Plateau.