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. <i>GDF9</i> and <i>BMPR1B</i> are major genes affecting the litter size of sheep. In this study, the whole coding region of <i>GDF9</i> was sequenced and all the SNPs (single nucleotide polymorphisms) were determined in Luzhong mutton ewes. The <i>FecB</i> mutation was genotyped using the Sequenom MassARRAY^®SNP assay technology. Then, the association analyses between polymorphic loci of <i>GDF9</i> gene, <i>FecB,</i> and litter size were performed using a general linear model procedure. The results showed that eight SNPs were detected in <i>GDF9</i> of Luzhong mutton sheep, including one novel mutation (g.41769606 T > G). The g.41768501A > G, g.41768485 G > A in <i>GDF9</i> and <i>FecB</i> 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 <i>GDF9</i> 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.