Polymorphism of Prolificacy Genes (BMP15, BMPR 1B and GDF9), in the Native Goat (Capra hircus) of Cameroon

Abstract

The main objective was to contribute to a better understanding of molecular characteristics of the local goat in order to improve its productivity and specifically to: analyse genetic polymorphism of three prolificacy genes (BMP15, BMPR1B, and GDF9) and test the association of genetic polymorphism and prolificacy of local goats. Tissue samples were collected from 446 animals, and 24 representative female goats were selected to analyse the genetic polymorphism of the prolificacy genes. The selected goats were divided into two groups of 12 females for high prolificacy (more than three kids consecutively in four parity) and 12 females for low prolificacy (less than two kids consecutively in four parity). Chi-square was used to test the association between genetic polymorphism and prolificacy of local goat. The main results showed that BMP15 gene is monomorphic, whereas the two other genes (BMPR1B and GDF9) display polymorphism. For BMPR1B gene, the ten mutations found did not change the corresponding amino acid. Allelic and genotypes frequencies of mutations of this gene varied from one mutation to another and between the two groups of females (high and low prolificacy). Chi-square test of the polymorphism of this gene shows that C34T and A120G mutations of exon 3 are significantly associated (p < 0.05) with prolificacy and can be considered as potential genetic markers for improving prolificacy in the native goat. For the GDF9 gene, three mutations were detected in exon 1 with alleles A and G1 of frequency 0.261 and 0.130 for A35G; G2 and C1 of frequency 0.696 and 0.304 for G81C; then G3 and C2 of frequency 0.696 and 0.304 for G255C. The mutations G81C and G255C appeared under BLAST and were missense mutations P27A and A85G respectively while A35G is located in the non-translated 5’ region of the gene. Chi-square test between each genotype for any site and the prolificacy was not significant (P > 0.01) suggesting that these two characters are not associated. Two mutations were detected in exon 2 at C881T and A1160G sites with C and T and A and G alleles respectively. The two mutations changed the corresponding amino acid from Alanine to Valine at the position 273 in the protein and from Valine to Isoleucine at the position 397 in the protein respectively. Allelic and genotypes frequencies of mutations varied from one mutation to another and between the two groups of females (high and low prolificacy). Chi-square test of the polymorphism shows that, although C881T and A1160G mutations were not significantly associated (P > 0.05) with prolificacy, the alleles responsible for the variation of amino acid increased the litter size. Therefore, further studies with increased sample size will help to verify the results.