Polymorphisms Analysis of BMP15, GDF9 and BMPR1B in Tibetan Cashmere Goat (Capra hircus)

Abstract

The Tibetan cashmere goat is a prolific goat breed in China. In sheep breeds, natural mutations have demonstrated that the transforming growth factor beta (TGF-β) super family ligands, such as growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15) and their type I receptor (bone morphogenetic protein receptor (BMPR1B), are essential for ovulation and increasing litter size. In this study, 216 female Tibetan cashmere goats were sampled, and candidate genes with fecundity traits were detected via restriction fragment length polymorphism (RFLP) and sequenced. Four polymorphic loci were found in specific amplification fragments of BMP15 and GDF9. Two SNP sites of the BMP15 gene were discovered, namely G732A and C805G. The G732A mutation did not cause the change in amino acids, and the frequencies of each genotype were 0.695 for the GG type, 0.282 for the GA type and 0.023 for the AA type. The C805G mutation caused amino acids to change from glutamine to glutamate. The genotype frequencies were 0.620 for the CC type, 0.320 for the CG type and 0.320 for the CG type. For the GG type 0.060, the G3 and G4 mutations of the GDF9 gene were all homozygous mutations. Two known SNP sites, C719T and G1189A, were detected in the Tibetan cashmere goat GDF9 gene, of which the C719T mutation caused a change of alanine to valine, with a genotype frequency of 0.944 for the CC type and 0.056 for the CT type, whereas no TT type was found. The G1189A mutation caused valine to become isoleucine, and the frequencies of each genotype were 0.579 for the GG type, 0.305 for the GA type and 0.116 for the AA type; G1, B2, B3, B4, FecXH, FecXI, FecXL, G2, G5, G6, G7, G8, FecGE, FecTT and FecB mutations were not found in Tibetan cashmere goats. The results of this study provide a data basis for future studies of BMP15, GDF9 and BMPR1B gene mutations in goats.