PCR-RFLP-based identification of polymorphisms in BMPR1B, GDF9 and BMP15 genes associated with litter size in Beetal and Teddy goats
The genes BMPR1B, GDF9 and BMP15 are oocyte-derived members of the transforming growth factor-β superfamily, which is essential for follicular growth and ovulation. The aim of the current study was to determine the incidence of reported mutations in exon 3 of BMPR1B gene, exon 1 of GDF9 gene, and exon 2 of BMP15 gene and their association with litter size in three parities of Beetal and Teddy goats. Based on the known mutations in these genes, PCR primers were designed to find out the polymorphism through the PCR-RFLP technique in 120 randomly selected animals of the two breeds, which vary in their prolificacy. The current results show that there were significant differences in litter size [1.708 ± 0.060 in Beetal (B) and 2.167 ± 0.056 in Teddy (T) goats] in both breeds. The results of breed x parity interaction showed significant differences in litter size in first [1.158 ± 0.061 (B); 1.861 ± 0.057 (T)], third [2.062 ± 0.078 (B); 2.583 ± 0.073 (T)] and average parity [708 ± 0.060 (B); 2.167 ± 0.056 (T)] in both breeds. All three loci in both breeds were found to be polymorphic and the results of breed x parity x genotype analysis showed that genotypes of all the three genes were significantly associated with litter size in all parities in both breeds. For the BMPR1B gene, heterozygous (CT) animals of Beetal and Teddy goats had the largest litter size in all three parities and the average (parity) litter size, showing the overdominance of the heterozygotes. Similarly, for GDF9 gene, heterozygous animals (AG) had the largest litter size in both breeds. For BMP15 gene homozygous carrier animals (CC) of both breeds had the highest number of kids, followed by the heterozygous (AC) genotypes. The current results show the importance of BMPR1B, GDF9 and BMP15 as the major genes that influence prolificacy in both Beetal and Teddy goats. It is suggested that these polymorphisms can be used as molecular markers to select the prolific animals in these breeds.
Keywords: Beetal goats, Teddy goats, molecular markers, prolificacy, polymorphism