Polymorphism Detection of GDF9 Gene and Its Association with Litter Size in Luzhong Mutton Sheep (Ovis aries)

Abstract

Litter size is one of the most important economic traits in sheep. GDF9 and BMPR1B are major genes affecting the litter size of sheep. In this study, the whole coding region of GDF9 was sequenced and all the SNPs (single nucleotide polymorphisms) were determined in Luzhong mutton ewes. The FecB mutation was genotyped using the Sequenom MassARRAY®SNP assay technology. Then, the association analyses between polymorphic loci of GDF9 gene, FecB, and litter size were performed using a general linear model procedure. The results showed that eight SNPs were detected in GDF9 of Luzhong mutton sheep, including one novel mutation (g.41769606 T > G). The g.41768501A > G, g.41768485 G > A in GDF9 and FecB were significantly associated with litter size in Luzhong mutton ewes. The g.41768485 G > A is a missense mutation in the mature GDF9 protein region and is predicted to affect the tertiary structure of the protein. The results preliminarily demonstrated that GDF9 was a major gene affecting the fecundity of Luzhong mutton sheep and the two loci g.41768501A > G and g.41768485 G > A may be potential genetic markers for improving litter size.

Polymorphism of the gene GDF9 in sheep of Prikatun type of Altai Mountains breedand its correlation with indices of meat rate productivity

“…The obtained data prove the feasibility of studying the influence of the gene GDF9 on the meat rate productivity of sheep of other breeds, in particular, A alleles and AA and AG genotypes. This is also promising from the point of view that a range of researches have demonstrated that the AG genotype has a positive effect on fertile multiplicity of ewes [20,21,22]. All thing being equal, getting more lambs provides increase of mutton rate production, which largely determines the economic efficiency of meat sheep farming.…”

“…The majority of studies witness a link between the growth differentiation factor gene and the reproductive qualities and fertile multiplicity of sheep [20,21,22]. It has been shown that GDF9 expression is significantly higher in ovarian tissues than in other body tissues, while the protein product of the gene plays an important role in maintaining the normal folliculogenesis [23,24].…”

Detection of Novel Variations Related to Litter Size in BMP15 Gene of Luzhong Mutton Sheep (Ovis aries)

“…The fixed model was y = μ + G1 + G2 + G1G2 + e , where y is the phenotypic value of litter size, μ is the population mean, G1 is the fixed effect for FecB genotype or GDF9 genotype, G2 is the fixed effect for BMP15 genotype, G1G2 is the fixed interaction effect of FecB and BMB15 combined genotypes or GDF9 and BMB15 combined genotypes and e is the residual error. The GDF9 and FecB data were analyzed in our previous report [ 23 ], and results indicated that the SNPs ENSOART00000014382.1:c.994G>A (rs421019907) and c.978A>G (rs399579080) in the GDF9 gene were significantly associated with litter size. Because these two SNPs are linked, we selected one of them (c.994G>A) to analyze its interaction with the SNPs in BMP15 .…”

“…The Luzhong mutton sheep is a new breed, and it has high fertility and meat production performance. It was developed by crossbreeding Hu sheep from China with White-headed Dorper sheep from South Africa [ 23 ]. Litter size records of Luzhong mutton sheep showed large variations between individual ewes, ranging from one to four.…”

“…Therefore, the first objective in the present study was to detect the polymorphism in the open reading frame (ORF) of BMP15 and assess its association with litter size in Luzhong mutton sheep. Our previous study identified multiple variations in GDF9 of Luzhong mutton sheep [ 23 ]. On the other hand, the maternal Hu sheep carries a high frequency of FecB mutations [ 26 , 27 ].…”