# Effect of GnRHR, BMP6 and FSHR Gene Pyramiding on Litter Traits of Goats

## TL;DR

This study identifies gene variants in GnRHR, BMP6, and FSHR that are linked to higher litter sizes in goats, offering a strategy for improving goat reproduction through genetic selection.

## Contribution

The novel contribution is the identification of optimal SNP combinations in three genes that synergistically enhance goat prolificacy through polygenic pyramiding.

## Key findings

- Four SNPs in GnRHR, BMP6, and FSHR were associated with increased litter size in Chongqing, Chuanzhong, and Leizhou goat breeds.
- Polygene polymerizing analysis identified optimal genotype combinations (e.g., AATTCC, AACCAACC) that enhance prolificacy.
- Reproductive tissues of high-prolific goats showed higher expression of GnRHR, BMP6, and FSHR genes.

## Abstract

With the increasing demand for goat meat by humans, increasing goat production to meet the demand for a healthy diet is an urgent task in the current livestock industry. In the production of small ruminants, it is particularly important to enhance their reproductive capacity, especially the litter-giving characteristics of does. Identifying key fecundity genes and utilizing polygene polymerizing effect analysis in goats can enhance litter size and improve production efficiency in the livestock industry. This study aimed to identify SNPs in the GnRHR, BMP6, and FSHR genes across four goat breeds, examine their association with litter size, and analyze the polygenic pyramiding effect on goat prolificacy. Our research identified four SNPs, and polygene polymerizing effect analysis further determined the optimal combination genotype that affects high prolificacy in goats. Overall, our results provide a foundation for molecular marker selection related to goat litter-size traits and a useful strategy for the further development of goat breeding.

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 GnRHR, BMP6, and FSHR gene polymorphisms on litter traits in four goat breeds (Chongqing black, Chuanzhong black, Leizhou, and Nubian). Single nucleotide polymorphisms (SNPs) (g.75G > A in GnRHR, g.951T > C in BMP6, and g.-112C > T/g.3236C > A in FSHR) 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 (GnRHR), CC (BMP6), TT (FSHR), and AA (FSHR) 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 GnRHR, BMP6, and FSHR 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.