Comparative Histomorphometric and Transcriptomic Analysis Reveals Potential Genetic Determinants of Pelage Variation Between Hairy and Coarse-Woolly Sheep

The study conducted a comparative histomorphometric and transcriptomic analysis of Australian White Sheep (hairy phenotype) and Hu Sheep (coarse-woolly phenotype) to uncover genetic determinants of pelage variation. It identified three fiber types in Australian White Sheep, while Hu Sheep lacked kemp fibers and had longer hair fibers with less subcutaneous fat. The analysis revealed 370 differentially expressed genes, with those in Australian White Sheep linked to lipid metabolism and those in Hu Sheep associated with immune functions. Key genes like KAP20-2, KRT6A, and EDA2R were linked to differences in fiber traits such as curvature and length. The findings suggest subcutaneous adiposity and immunoregulation as modulators of pelage divergence, offering targets for breeding climate-resilient and cost-effective sheep.