Sequences Analysis And Polymorphism Study Of Myostatin Gene In Tianzhu White Yak

The study about yak population myostatin (MSTN) gene was rarely reported. The full sequence of Tianzhu white yak MSTN gene, bioinformatics research and polymorphism analysis was never reported. In this study, the full sequence of Tianzhu white yak MSTN gene was cloned and sequenced. The sequence structure, composition of nucleotide, and encoded amino acid were analyzed by bioinformatics, and the molecular evolutionary tree was established. Furthermore, the polymorphism of the partial nucleotide sequence of Tianzhu white yak MSTN gene was analyzed by PCR-SSCP. The results as follows:1. The MSTN gene sequence was amplified by PCR in Tianzhu white yak. Bioinformatics analysis shows:(1) The full DNA sequence was 5083bp in length, including 3 exons and 2 introns. The length of 3 exons was 373bp, 374bp and 381bp respectively, the length of 2 introns was 1844bp and 2030bp respectively. The cDNA was 1128bp with aunique ORF.(2) The MSTN gene of Tianzhu whit yak has low level of G+C%, but the coding regionshas higher G+C% compared with intros.(3) There were 375 amino acids in Tianzhu white yak MSTN protein sequence was predicted, and the protein's molecular weight was about 42551.07D, isoelectric point was about 6.369. The structure of amino acids sequence shared the same feature with other animals, as cleavage at the predicted RSRR proteolytic site producing a mature peptide which contained 9 cysteine residues.(4) The contents of 20 kinds of amino acids of MSTN in Tianzhu white yak were unbalanced, and the usage of synonymous codons was very strong biased.(5) Phylogenetic analysis suggests that the MSTN gene molecular evolution tree and species tree was similar on structure, and the homologies of protein sequence higher than cDNA sequence in several animals.2. SSCP analysis and DNA sequence analysis shows:(1) There was no polymorphic site was detected in the P1/P2 primer amplified 422bp sequence of MSTN gene in 698 white yak, which including 78bp 5'-UTR partial sequence and 344bp partial sequence of exon1.(2) Five polymorphic sites were found in the P3/P4 primer amplified 556bp sequence of MSTN gene in 698 white yaks, which including full sequence of exon 2, 80bp sequence of intro 1 and 102bp sequence of intro 2. These polymorphic sites formed 4 genotypes, named AA, BB, AB and AC, controlled by alleles A, B and C, the genotype frequency was 0.8840, 0.0014, 0.1060 and 0.0086 respectively. one Aâ†'G transition at 704bp of cDNA in allele B, results in the substitution of a His by a Arg; the other 4 mutation sites in allele C, one Gâ†'A transition at 1795 bp of intro 1, one single nucleotide deletion at 1829bp of intro 1, one Gâ†'A transition at 75bp of intro 2, and 1 Câ†'T transition synonymous mutation at 414 bp of cDNA. And the higher nucleotide mutation rate of C allele was speculated due to insertion/deletion mutagenic effects.(3) One mutation site was detected in the P5/P6 primer amplified 375bp sequence of MSTN gene in 698 white yaks, which including 377bp partial seguence of exon3 and 4 bp partial seguence of 3'-UTR. Only 1 Aâ†'G transition was found at this region, it is a synonymous mutation site, and formed 3 genotypes, named DD, EE and DE, controlled by alleles D and E, the genotype frequency was 0.8926, 0.0014 and 0.1060 respectively.(4) Individuality of DD, and AA or AC genotype was found in population of 698 white yaks, and DD genotype located in the amplifing region of primers P5/P6, and AA or AC genotype located in the amplifing region of primers P3/P4. But Frequency for AC is much less than that of AA. Individuality of DE genotype which is located in the amplifing region of primers P5/P6 manifested as BB genotype which is located in the amplifing region of primers P3/P4. Whereas, individuality of DE genotype which is located in the amplifing region of primers P5/P6 manifested as AB genotype which is located in the amplifing region of primers P3/P4.