Ovarian expression, polymorphism identification and association of SIRT3 gene with reproduction traits in goats.

The NAD+-dependent protein deacetylase, Sirtuin3 (SIRT3), plays a role in fertility by preventing the activation of reactive oxygen species (ROS). A novel study was conducted on caprine SIRT3, to study its ovarian expression, explore the sequence variability in exon 7 and analyze its association with prolificacy in two native goat breeds of Kerala, Malabari and Attappady Black. The mRNA isolated from ovaries of six Malabari and Attappady Black goats were subjected to quantitative PCR (qPCR) using GAPDH and ß-actin as reference genes. Genomic DNA was isolated from 185 goats (99 Malabari and 86 Attappady Black) and subjected to PCR-SSCP to identify polymorphism in exon 7 of SIRT3 and association with litter size was analyzed. The ovarian expression of caprine SIRT3 was significantly higher (p ≤ 0.01) in Malabari than low prolific Attappady Black. PCR-SSCP analysis revealed, exon 7 of SIRT3 was polymorphic with three genotypes namely, AA, AB and BB with a novel SNP, g.154C > T in the 3'UTR. A significant association (p ≤ 0.05) was noticed between the genotypes of SIRT3 and litter size. The results obtained from this study highlight the role of SIRT3 in reproduction and hence SIRT3 may be considered as a potential candidate gene for genetic improvement in goats.

Nerve Growth Factor gene ovarian expression, polymorphism identification, and association with litter size in goats.

The Nerve Growth Factor (NGF) plays an important role in reproduction by augmenting folliculogenesis. In this study, the coding regions of caprine NGF gene were analyzed to detect single-nucleotide polymorphisms (SNPs), their association with litter size, and the relative ovarian expression of NGF gene in the two indigenous goat breeds of South India viz., the prolific Malabari and less-prolific Attappady Black. The sequence analysis of the third exon containing the entire open reading frame of NGF gene was observed to be of 808 bp with one nonsynonymous mutation at 217th position. Later, polymerase chain reaction (PCR) was performed to amplify a region of 188 bp covering the region carrying the detected mutation. The genomic DNAs from the goats under study (n = 277) were subjected to PCR and single strand conformation polymorphism (SSCP). On analysis, four diplotypes viz., AA, AB, AC, and AD were observed with respective frequencies of 0.50, 0.22, 0.27, and 0.01. Sequencing of the representative samples revealed an additional synonymous mutation, i.e., g.291C>A. Statistical analysis indicated that NGF diplotypes and the SNP g.217G>A were associated with litter size in goats (P < 0.05). Relative expression of NGF gene was significantly higher in the ovaries of goats with history of multiple than single births (P < 0.05). The results of the present study suggest the significant effect of the NGF gene on litter size in goats and identified SNPs would benefit the selection of prolific animals in future marker-assisted breeding programs. The two novel PCR-restriction fragment length polymorphisms designed, based on the detected SNPs, would help in the rapid screening of large number of animals in a breeding population for identifying individual animals with desired genetic characteristics.