Genetic Structure and Selection Signals for Extreme Environment Adaptation in Lop Sheep of Xinjiang

Lop sheep species exhibit remarkable adaptability to desert pastures and extreme arid climates, demonstrating tolerance to rough feeding and high resistance to stress. However, little is known about the population genetic diversity of Lop sheep and the genetic mechanisms underlying their adaptability to extreme environments.

Blood samples were collected from a total of 110 individuals comprising 80 Ruoqiang Lop sheep and 30 Yuli Lop sheep. A total of 110 Lop sheep were subjected to whole genome resequencing to analyze genetic diversity, population structure, and signatures of selection in both regions.

The genetic diversity of the Lop sheep population is substantial, and the degree of inbreeding is low. In comparison to the Lop sheep in Yuli County, the genetic diversity and linkage disequilibrium analysis results for the Lop sheep population in Ruoqiang County are slightly lower. Population structure analysis indicates that Ruoqiang and Yuli Lop sheep have differentiated into two independent groups. Using Yuli Lop sheep as the reference group, an analysis of the extreme environmental adaptability selection signal of Lop sheep was conducted. The FST and π ratio under the 1% threshold identified 1686 and 863 candidate genes, respectively, with their intersection yielding a total of 122 candidate genes. Functional annotation revealed that these genes are associated with various traits, including immune response (SLC12A2, FOXP1, PANX1, DYNLRB2, RAP1B, and SEMA4D), heat and cold resistance (DNAJC13, PLCB1, HIKESHI, and PITPNC1), desert adaptation (F13A1, PANX1, ST6GAL1, STXBP3, ACTN4, and ATP6V1A), and reproductive performance (RAP1B, RAB6A, PLCB1, and METTL15).

These research findings provide a theoretical foundation for understanding the survival and reproductive characteristics of Lop sheep in extreme environments, and they hold practical value for the conservation and utilization of Lop sheep genetic resources, as well as for genetic improvement efforts.