Simple Summary
Duolang sheep are a special local breed from Xinjiang, China, known for their high fertility and early maturity. They have been traditionally raised by the Uyghur people for both meat and fat production. However, little was known about their genetic background and the reasons behind their strong reproductive performance. In this study, we analyzed the whole-genome of 60 Duolang sheep to explore their genetic structure and identify genes related to reproduction. The results revealed rich genetic diversity and relatively low selection pressure in the population, indicating strong adaptability. We also detected several genetic regions that may be associated with reproductive traits. This research provides the first comprehensive genomic overview of Duolang sheep and offers valuable insights for conserving and improving this unique local breed, ensuring its sustainable development and continued contribution to local animal husbandry.
Abstract
Duolang sheep, a meat–fat dual-purpose breed indigenous to Xinjiang, China, has been cultivated traditionally by the local Uyghur people for its prolificacy and precocious sexual maturity, while little research on the population structure and trait inheritance characteristics of Duolang sheep is available. This study employed whole-genome resequencing data from a cohort of 60 Duolang sheep to dissect their genetic population structure and genes related to reproductive traits. A total of 1565 Gb of high-quality data with an average depth of 14.06´ was generated. After SNP calling and quality control, 31,300,060 SNPs were identified. Following linkage disequilibrium (LD)-based pruning, a total of 4,479,177 high-quality SNPs were retained for subsequent analyses. Based on these SNPs, the internal genetic structure of the Duolang sheep population was elucidated, with 14 kinship outliers detected through principal component analysis (PCA). Furthermore, LD decay analysis revealed that the r2 declined below 0.1 at approximately 10 kb, indicating a relatively low level of selection pressure in the population. Within the population, Tajima’s D and iHS methods detected 517,218 and 82,534 candidate SNPs under selection, respectively, with 24,453 SNPs overlapping between the two methods. By splitting Duolang sheep into single-lamb (n = 29) and multiple-lamb (n = 12) subgroups according to litter size, 267,654 SNPs were identified by XP-CLR, while 184,179 SNPs suffering from selection were detected by FST and 62,150 by XP-EHH. Functional enrichment analysis of selected genes reveals the selection directions (domestication, growth, and reproduction) and related candidate genes in the Duolang sheep population, including ESRRA, ESRRB, OXT, FSHR, ESR2, GNRHR, and BMPR1B. This study provides the first comprehensive genomic landscape of Duolang sheep, elucidating genetic signatures of its adaptive traits.