[Analysis on single nucleotide polymorphisms of porcine myostatin gene in different breeds]

By PCR-RFLPs and PCR-SSCP approach, three single nucleotide polymorphisms (SNPs) of porcine myostatin gene (MSTN) were analyzed in different breeds including "doubled-muscled" Yorkshire, Yorkshire, Landrace, Hamshire, Duroc, Piteran, Erhualian, Min, Hubei White and some hybrids. The three SNPs were located in the 3' encoding region, 5' promoter region and intronl region respectively. For the SNP in the 3' encoding region, which was caused by C-->T transition, the mutation frequency was relatively low: no TT genotype was detected in 274 individuals of different breeds. For the SNP in the 5' promoter region, 560 pigs were investigated. The allele T dominates in the imported lean-type pig breeds such as Yorkshire, Landrace, Duroc, Hampshire, Piteran and hybrid, however, in Erhualian and Hubei White pigs, the allele A was in majority. Polymorphism showed the similar pattern for the SNP in intron 1 region. G was the dominant allele in Yorkshire, Landrace and their hybrids, while in Erhualian and Hubei White pigs the frequency of A was much higher. Obviously they were not in Hardy-Weinberg equilibrium state. For Min and Yorshire x Erhualian pigs, they were in Hardy-Weinberg equilibrium state for the SNPs in the 5' promoter region and (or) intron 1 region. The frequency for the A alleles of SNPs in the 5' promoter region and intron 1 region was higher for "double-muscled" Yorkshire than for Yorkshire and linkage for these two mutation sites was also observed.