Effect of , and Gene Pyramiding on Litter Traits of Goats.

Many studies have shown that only a few breeds of goat have the trait of high fertility, and genes play an important role in regulating litter size. This study investigated the effects of , , and gene polymorphisms on litter traits in four goat breeds (Chongqing black, Chuanzhong black, Leizhou, and Nubian). Single nucleotide polymorphisms (SNPs) (g.75G > A in , g.951T > C in , and g.-112C > T/g.3236C > A in ) were genotyped using PCR-RFLP/HRM in 959 goats. Association analysis revealed significant correlations between these SNPs and litter size in the Chongqing, Chuanzhong, and Leizhou breeds, with genotypes AA (), CC (), TT (), and AA () linked to higher prolificacy. Polygene polymerizing effect analysis identified the optimal combinations (e.g., AATTCC, AACCAACC) with enhanced litter sizes. Tissue-specific qPCR in Chuanzhong goats showed , , and were significantly more highly expressed in reproductive tissues (pituitary, breast, ovary, oviduct) of the prolific group than those in the non-prolific group. These SNPs serve as potential molecular markers for improving goat litter traits through polygenic selection, emphasizing the synergistic impact of multi-gene interactions on prolificacy.