Single Nucleotide Polymorphisms (SNPs) Analysis On The First Exon Of Myostatin Gene (MSTN) In Grassland Red Cattle

Lean meat percentage is one of the most important economic target traits in cattle breeding programs, the percentage is closely related with the amount of the skeletal muscle. Myostatin as the member of TGF-β superfamily identified by McPherron in 1997, has caused extensively attention because of its negative regulator of skeletal muscle mass in mice.Double-muscled phenotype of Belgian Blue and Piedmontese beef cattle was caused by mutation of 11bp deletion and substitution of conserved base in bioactive region of myostatin gene(MSTN). Linkage analysis indicates that MSTN and mh gene in the same cluster on the chromosome, its genetic effect is to increase ratio of lean meat.This study selected MSTN as a candidate gene, and selected 13 grassland red cattle, 13 hybridism contained 1/4 blood of limousin and 3/4 blood of grassland red cattle and hybridism contained 1/2 blood of limousin as experiment material, identify the difference in nucleotide sequence of bioactive region through PCR-SSCP analysis method. PCR products with polymorphism fragements were cloned and sequenced to detect single nucleotide polymorphism and analysed the relationship between Double-muscled gene and the trait of beef breeding. The results listed as followed:(1) There was no polymorphism in the first exon of the myostatin gene in grassland red cattle and only exists AA gene type in this region.(2) A polymorphism in the first exon of the myostatin gene was found in the hybridism which contain 1/4 limousin cow's blood through PCR-SSCP method. There are two genotypes AA and AB and the allele's frequencies is 0.885 A and 0.115 B in this region.(3) A polymorphism in the first exon of the myostatin gene was found in the hybridism which contain 1/2 limousin cow's blood by PCR-SSCP method. There are three genotypes AA ,AB and BB and the allele frequencies is 0.731 A and 0.269 B in this region.(4) PCR products with polymorphism fragements were sequenced, the result indicated that a C→A mutation in the first exon of the myostatin gene leaded the mutation of coding amino acid from Phe to Leu.(5) The effect of MSTN gene's Mutation C→A up on bovine economic character were evaluated by least square analysis of SAS software package, which indicated a...