Effects of New Mutations in BMPRIB, GDF9, BMP15, LEPR, and B4GALNT2 Genes on Litter Size in Sheep

SIMPLE SUMMARY: BMPRIB, GDF9, BMP15, LEPR, and B4GALNT2 genes were regarded as leading candidates for reproductive traits in sheep. Our recent studies identified 13 novel mutations associated with litter size in the Mongolia sheep breed in these 5 genes. In this study, we performed an association analysis of the 13 new mutations and 7 known ovine prolificacy-related mutations with litter size in Ujimqin, the F1 population of Dorper × Ujimqin crossbred, and the F1 population of Suffolk × Ujimqin crossbred. The results suggested that BMPR1B c.746A>G (FecB), GDF9 c.994A>G (FecG(A)), and BMP15 c.31_33CTTinsdel (B1) may be potentially effective genetic markers to improve the litter size in sheep. ABSTRACT: Prolificacy is a crucial characteristic of livestock, particularly for species such as sheep that have many births. The objectives of this study were as follows: (1) to investigate the genetic diversity of the 13 new and 7 known variants in the BMPRIB, GDF9, BMP15, LEPR, and B4GALNT2 genes in Ujimqin (UM), the F1 population of Dorper × Ujimqin crossbred (DPU), the F1 population of Suffolk × Ujimqin crossbred (SFKU), Sonid sheep (SN), Tan sheep (Tan), Hu sheep (Hu), and Small-tailed Han sheep (STH) sheep breeds/populations; (2) to perform an association analysis of the above 20 variants with litter size in 325 UM, 304 DPU, and 66 SFKU sheep populations; (3) to compare the frequencies of the litter-size-related alleles of these 20 variants among 8 sheep breeds/populations (the above seven sheep breeds + Mongolia sheep breed). With the use of the Sequenom MassARRAY(®)SNP assay technology, these 20 mutations were genotyped. The association analysis results showed that the c.746A>G (FecB) mutation in BMPR1B was significantly associated with the litter size of UM and DPU, the c.994A>G (FecG(A)) in GDF9 was significantly associated with the litter size of SFKU, and the c.31_33CTTinsdel (B1) in BMP15 was significantly associated with the litter size of UM. Our findings might provide valuable genetic markers for expanding sheep litter sizes.