Large-scale low-coverage whole-genome sequencing reveals the genetic architecture of wool and growth traits in fine-wool sheep.

Breeding sheep with superior growth performance and wool quality is essential for the sustainability of the fine-wool sheep industry. In this study, we perform low-coverage whole-genome sequencing (lcWGS) on 3842 individuals from 5 sheep breeds (4 fine-wool and 1 semi-fine wool) and generate a large genomic dataset. By comparing these breeds with coarse-wool sheep, we characterize the genomic landscape and selection signatures of fine-wool sheep. We identify several known functional genes associated with hair follicle development and skin morphology, including EGFR, KRT74, EDAR, EREG, and GLI2. Furthermore, GWAS of 19 traits identifies 156 candidate genes significantly associated with growth and wool characteristics, including LCORL for body size, EGFR for clean wool yield, and PRDM1 for fiber diameter. Notably, EGFR is detected in both GWAS and selection signature analyses, indicating its important role in phenotype formation and historical selection. Overall, our findings reveal the genetic basis of growth and wool traits in fine-wool and semi-fine wool sheep, highlight EGFR, LCORL, and PRDM1 as candidate genes, and provide valuable genomic resources and candidate markers for future functional validation and molecular breeding.