Genetic Effects of Single Nucleotide Polymorphisms in the Goat GDF9 Gene on Prolificacy: True or False Positive?

Abstract

Simple SummaryAs an important regulator factor, which was secreted by female oocytes, the growth differentiation factor 9 (GDF9) plays an essential role during the growth and differentiation of ovarian follicles. Single nucleotide polymorphisms (SNPs) within the GDF9 gene have been found to be involved in reproductive traits in livestock, and some of these mutations have been used as the effective makers in animal molecular breeding. However, it is remarkable that the SNPs of the goat GDF9 gene have not been systematically sorted and analyzed from the reported studies, which leads to an inability to find effective loci that could be applied in improving the prolificacy of goats via the molecular breeding method. In this study, we gathered and sorted 45 SNPs of the goat GDF9 gene from all relevant studies and the National Center for Biotechnology Information Search database (NCBI), and especially analyzed and discussed the relationship between part controversial and potentially effective SNPs and the reproductive traits. The results indicated that non-synonymous SNPs A240V, Q320P, and V397I and synonymous SNPs L61L, N121N, and L141L were six “true” positive SNPs in improving goat fertility. Nevertheless, the regulation pathways and the specific mechanism of these six SNPs on goat fecundity are not clear, which still need further study in more goat breeds and a large sample size. These results provided an effective tool for follow-up research studies on the molecular genetic breeding of goats’ reproductive traits.AbstractGoat reproductive traits are complex quantitative traits controlled by polygenes and multipoint. To date, some high-fertility candidate genes in livestock have been unearthed and the growth differentiation factor 9 (GDF9) gene is one of them, which plays a crucial role in early folliculogenesis. According to the relevant previous studies and the National Center for Biotechnology Information Search database (NCBI), a total of 45 single nucleotide polymorphisms (SNPs) have been detected in the goat GDF9 gene, but which one or which ones have important effects on goat fecundity is still uncertain. Hence, in order to find effective molecular markers for goat genetic breeding and accelerate the goat improvement, this study summarized and classified the above 45 SNPs into four kinds, as well as compared and analyzed the same SNP effects and the different SNPs linkage effects on the reproductive traits in different goat breeds. Since there were many SNPs in the goat GDF9 gene, only 15 SNPs have been identified in more than 30 goat breeds worldwide and they showed different effects on the litter size. Therefore, this study mainly chose these 15 SNPs and discussed their relationship with goat productivity. Results showed that three non-synonymous SNPs A240V, Q320P, and V397I and three synonymous ones L61L, N121N, and L141L played a “true” role in the litter size trait in many goat breeds around the world. However, the regulatory mechanisms still need further research. These results provide an effective tool ...

Detection of rs665862918 (15-bp Indel) of the HIAT1 Gene and its Strong Genetic Effects on Growth Traits in Goats

“…In previous studies, SNPs in genes were shown to be associated with growth traits and litter size in goats [30][31][32][33]. Indels similarly present relationships with growth traits [34,35], as observed for a 12 bp indel in GDF9 that is related to first-born litter size in goats [4], and a 14 bp indel in CMTM2 that shows a relationship with litter size in goats [24].…”

Mutations in NLRP5 and NLRP9 Are Associated with Litter Size in Small Tail Han Sheep

“…GDF9 has been proven to be highly associated with litter size in sheep (Small Tail Han sheep) [10,21], goats [22,23], and even dogs [24]. Ongoing research has revealed some potential mechanisms underlying this association.…”

TGIF1 and SF1 polymorphisms are associated with litter size in Small Tail Han sheep

“…Understanding the genetics of reproduction is important for the sheep industry, and recent researches have revealed that the regulation of litter size in sheep and goats is multiallelic and polygenic (Wang et al, 2019;Zhang et al, 2020). For example, FecB is a prominent gene affecting litter size, and ewes with the genotype of FecB BB carry two copies of a FecB mutation.…”