Polymorphism of exon 1 of INHA gene and its relationship with prolificacy in sheep
Inhibin A(INHA) gene was studied as a candidate gene for the prolificacy of Small Tail Han sheep. Single nucleotide polymorphism of exon 1 of INHA gene was detected in both high fecundity breeds(Small Tail Han and Hu sheep) and low fecundity breeds(Dorset, Texel and German Mutton Merino sheep) by PCR-SSCP. Results indicated that there were two genotype(sAA and AB)in all five sheep breeds tested. Frequency of allele B was 0.21 and 0.47 in prolific Small Tail Han and Hu sheep, respectively. Frequency of allele B was 0.07,0.10 and 0.02 in Dorset, Texel and German Mutton Merino sheep, respectively. Sequencing revealed a T→C mutation at 877 bp of exon 1 of INHA gene in the AB genotype in comparison to the AA genotype. The INHA genotype distributions were significantly different(P0.05) among high fecundity sheep breeds and low fecundity sheep breeds. The Small Tail Han ewes with heterozygous genotype AB had 0.57(P0.01) lambs more than those with genotype AA.