Recently, a study entitled ‘Structural variants selected during yak domestication inferred from long-read whole-genome sequencing’ by the State Key Laboratory of Grassland Agroecosystems and Institute of Ecological Innovation, was published online as a Letter in Molecular Biology and Evolution, which is a famed international journal in the field of evolutionary ecology.、

The study reported a high-quality reference genome of domestic yak, Bos grunniens. By further sequenced 29 yak individuals with Nanopore sequencing, researchers constructed a comprehensive map of structural variants (SVs) in yaks, revealed the role of SVs in the domestication of yak. Their findings provide new insights into the genetic mechanism of yak domestication and the role that SVs play in animal domestication and adaptive evolution.

Domestic yak is a species belongs to Bos genus living in the altitude of 3,600-6,000 m on Qinghai-Tibetan Plateau (QTP) and is generally considered to be descendant of the wild yak. They provide an important resource for the survival and livelihood of nomadic people living on QTP. Previous researches reported that the domestic yak was domesticated about 7,000 years ago, genes related to neurological development and traits were subject to strong artificial selection during the domestication process.

In this research, the authors sequenced and assembled a reference genome of 3.83 Gb with various sequencing strategy. With Hi-C sequencing, the sequences were further anchored onto 31 chromosomes. The reference genome is the most contiguous genome of yak, the most complete genome across all ruminant genomes as well.

Using 98 short-read yak sample and 29 long-read ones, they identified a total of 27,220 SVs in yak population, which was constituted by 328,936 deletions, 32,618 insertions, 4,321 duplications, 1,993 inversions and 4,352 translocations. These SVs represents the first comprehensive SV genetic map of yak.

Furthermore, the authors identified 3,680 SVs that were highly diverged between wild and domestic yaks and were considered as potential domestication-related SVs. 725 SVs were in genes or upstream/downstream regions of genes, whose functions mainly focus on domestication traits such as nervous system development and depression.

Prof. Jianquan Liu was the corresponding author of this paper. Graduate students Shangzhe Zhang, Wenyu Liu and Xinfeng Liu from State Key Laboratory of Grassland Agroecosystems and Institute of Ecological Innovation are tied for first authorship. This research is supported the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (2019QZKK0502), the national youth talent support program (Q.Q.), National Natural Science Foundation of China (31661143020, 41620104007), the Fundamental Research Funds for the Central Universities (Grant No. lzujbky-2019), and International Collaboration 111 Programme (BP0719040). Computing resources were supported by Big Data Computing Platform for Western Ecological Environment and Regional Development and Supercomputing Center of the Lanzhou University.

This is one of the series of researches of the group's long-term study on yaks. The previous researches were published in Nature Genetics, Nature Communications, Molecular Biology and Evolution and other internationally renowned journals, and have been widely noticed and cited.