Exploring the Sheep MAST4 Gene Variants and Their Associations with Litter Size

The economic efficiency of sheep breeding can be improved by enhancing sheep productivity. A recent genome-wide association study (GWAS) unveiled the potential impact of the MAST4 gene on prolificacy traits in Australian White sheep (AUW)). Herein, whole-genome sequencing (WGS) data from 26 different sheep breeds worldwide (n = 1507), including diverse meat, wool, milk, or dual-purpose sheep breed types from China, Europe, and Africa, were used. Moreover, polymerase chain reaction (PCR) genotyping of the MAST4 gene polymorphisms in (n = 566) Australian white sheep (AUW) was performed. The 3 identified polymorphisms were not homogeneously distributed across the 26 examined sheep breeds. Findings revealed prevalent polymorphisms (P3-ins-29 bp and P6-del-21 bp) with varying frequencies (0.02 to 0.97) across 26 breeds, while P5-del-24 bp was presented in 24 out of 26 breeds. Interestingly, the frequency of the P3-ins-29 bp variant was markedly higher in Chinese meat or dual-purpose sheep breeds, while the other two variants also showed moderate frequencies in meat breeds. Notably, association analysis indicated that all InDels were associated with AUW sheep litter size (p < 0.05). These results suggest that these InDels within the MAST4 gene could be useful in marker-assisted selection in sheep breeding.