Molecular Markers On The Polymorphism Of Bovine Myostatin Gene

MSTN gene belongs to the transforming growth factor-βsuperfamily and is expressed specifically in developing and mature skeletal muscle.The expression product of MSTN gene can inhibits muscle growth and differentiation.Mutation occurred in the conservative region of MSTN gene make the gene loss its function and cause skeletal muscle hyperplasia and hypertrophy.The polymorphism of myostatin gene and the relationship between polymorphism and cattle production trait were studied in this paper. The goal is try to find a molecular marker for cattle lean meat percentage. DNA was isolated from the blood of 45 Nanyang cattle ,30 Qinchuan cattle and 35 Piedmontese. PCR-SSCP was used to investigate the polymorphism in the third exon of myostatin , PCR products with polymorphism fragements were cloned and sequenced to detect single nucleotide polymorphism.The results show that:1. A polymorphism in the third exon of the myostatin gene was find in Nanyang cattle by PCR-SSCP. Two genotypes AA and AT were exist with allele frequencies 0.9889 A and 0.0111 T.2. A polymorphism in the third exon of the myostatin gene was find in Piedmontese by PCR-SSCP. The genotypes are the same to Nanyang cattle and allele frequencies 0.9857 A and 0.0143 T. The results are same to Me' s.3. There was no polymorphism in the third exon of the myostatin gene in Qinchuan cattle.4. A and T allele frequencies in the three breeds show that T allele frequencie was very small.It also shows that there was higher T allele frequencies in Piedmontese than Nanyang cattle and Qinchuan cattle and there was more double muscled catties in Piedmontes.5. The relationship between polymorphism in the third exon and production traitof Nanyang cattle and Piedmontese was analysed.Variance analysis showed that there was significant relationship between the polymorphism and birth weight ,the yearing weight, 18 month weight (P<0.05) . There was also significant relationship between AT genotype and birth weight ,the yearing weight, 18 month weight (P<0.05) .6.The fragments with SSCP in the third exon was cloned and sequenced,the sequence results showed that there was a single nuclotide mutation at position 938, G mutated to A.This mutation made the amino acid Cystine was replaced by Tyrosine,so the myostatin protine was inactive.7.A double muscled bovine was first find in Nanyang cattle.8. A simple PCR-SSCP based myostatin detection system has been developed .