Screening for signatures of selection of Tianzhu white yak using genome‐wide re‐sequencing

Abstract

The Tianzhu white yak, a domestic yak indigenous to the Qilian Mountains, migrated inland from the Qinghai-Tibet Plateau. Specific ecological and long-term artificial selection influenced the evolution of its pure white coat and physiological characteristics. Therefore, it is not only a natural population that represents a genomic selective region of environmental adaptability but is also an animal model for studying the pigmentation of the yak coat. A total of 24 261 829 variants, including 22 445 252 SNPs, were obtained from 29 yaks by genome-wide re-sequencing. According to the results of a selective sweep analysis of Tianzhu white yak in comparison to Tibetan yaks, nine candidate genes under selection in Tianzhu white yak were identified by combining p, Tajima's D, pA/pB and F ST statistics, with threshold standards of 5%. These genes include PDCD1, NUP210, ABCG8, NEU4, LOC102287650, D2HGDH, COL4A1, RTP5 and HDAC11. Five of the nine genes were classified into 12 molecular signaling pathways, and most of these signaling pathways are involved in environmental information processing, organismal systems and metabolism. A majority of these genes has not been implicated in previous studies of yak coat color and high-altitude animals. Our findings are helpful not only for explaining the molecular mechanism of yak coat pigmentation but also for exploring the genetic changes in Tianzhu white yak due to environmental adaptation.

Adaptation Mechanisms of Yak (Bos grunniens) to High-Altitude Environmental Stress

“…Camk2b, Gcnt3, Hsd17b12, Whsc1, and Glul High level of nutrition utilization in high altitudes [13] HIF1A, MMP3, ADAM17, ARG2 High-altitude adaptation [13] DEXI, DCC, and MRP4 Adaptation to high-altitude environments [14] PDE4D, RPS6KA6, ITPR1, and GNAO1 Environmental information processing and environmental adaptability [20] EPAS1 Key transcription factor that activates the expression of oxygen-regulated genes [21] ABCG8, COL4A1, LOC102287650, PDCD1, and NUP210 Adaptation to high-altitude environments [22] VEGF-A Regulation of blood vessel size [35] MMP3…”

“…Knowledge of the mechanisms underlying adaptation to various agro-ecosystems is essential for the effective management of farm animal genetic resources [7,19]. Intriguingly, multiple studies have focused on yak adaptation, allowing researchers to understand the morphological, physiological, biochemical, and genetic mechanisms of adaptation to extremely high altitudes [13,15,[20][21][22]. Although research on the adaptation mechanisms of the yak in high altitudes has increased exponentially, review studies on the comprehensive, adaptive mechanisms remain scarce.…”