White yak in Namtso  Photo by Sergio Capuzzimati on Unsplash

 

The research, conducted by scientists from the Institute of Innovation Ecology and the State Key Laboratory of Grassland Agro-ecosystems at Lanzhou University , was published in Molecular Biology and Evolution in May, in an article entitled “Structural variants selected during yak domestication inferred from long-read whole-genome sequencing.” 

 

SVs are large genomic alterations that represent an important genetic resource for both natural and artificial selection. Using genome resequencing data from six wild and 23 domestic yaks, the researchers drew a map of 372,220 structural variants (SVs) covering the geographic range of yaks on the Qinghai-Tibetan Plateau (QTP). 

 

By comparing genetic distances, they identified 3,680 SVs in the domestic yaks that are highly diverged from the wild ones, implying that the genes reflect exposure to human impact. “The genes concerned are mainly related to yaks’ nervous system, behavior, immunity capability, and reproduction, which may be targeted under artificial selection during the domestication of yaks.” said Prof. LIU Jianquan  from Lanzhou University, corresponding author of the study.

 

As part of this study, the researchers were also able to obtain a domestic yak genome sequence of higher quality than previously reported genomes.

 

These findings offer insight into how animals living at high altitude were domesticated and highlight the importance of genetic structural variants in animal domestication. Studying yak domestication mechanisms is important for research on their conservation. Since the species is critical to the livelihood of nomads in the Third Pole region, such research is vital.

 

Previous studies have found that wild yaks were domesticated about 7,100 years ago, producing the species Bos grunniens, around the same time human activity expanded to the Third Pole. During the domestication process, some genes related to neurological development were subject to significant artificial selection, according to previous research. 

 

China has about 13 million yaks, which, as a species, can withstand extremely cold and harsh climate conditions at high altitude, according to  the Encyclopedia of Animal Science. The meat, milk, down and feces of domestic yaks are all put to human use, while wild yaks are a protected species.

 

Editor’s note: The study is supported by STEP, a TPE related science project.