Abstract
Tong sheep, known for their superior meat quality and disease resilience, face breeding challenges due to low prolificacy, unlike Hu sheep, which exhibit higher fertility and growth rates. This study identified over 700,000 genetic variants between these breeds through pooled whole-genome sequencing. Functional analysis reveals key differences in pathways related to fat metabolism, insulin signaling, and cell cycle regulation. Notable findings include unique microRNA variants (miR-1185-3p in Tong sheep and miR-487-5p in Hu sheep), with the miR-487-5p mutation potentially regulating KITLG, a fertility-related gene. These results suggest that non-coding RNA mutations contribute to phenotypic differences and provide a genomic foundation for molecular-assisted selection to improve Tong sheep breeding programs.