The Analysis for the Single Nucleotide Polymorphism of TGF-β1 and Its Association with Reproduction in Different Sheep Breeds

A single nucleotide polymorphism (SNP) of 805 bp region in the intron 6 of transforming growth factor β1 (TGF-β1) gene was identified by polymerase chain reaction-single-strand composition polymorphism (PCR-SSCP) in 196 sheep among Small-tailed Han sheep, Tong sheep, Tan sheep and Oula sheep. Comparative sequence analysis of cloned products revealed an AGAC deletion at 294 bases upstream of exon 7 of the TGF-β1 gene (site 14201 in gi76871756). Statistical results of the genotype and allele frequencies in different breeds showed that genotype AB was dominant in the Small-tailed Han sheep. Genotype BB, however, was in majority in low-fecundity sheep. The results of a Chi-square test indicated that all the populations were in Hardy-Weinberg equilibrium.