Study On Polymorphism And Sequence Of Myostatin (MSTN) Gene In Tibetan Pig

In this thesis, the polymorphisms of myostatin gene three complete exons in Tibetan pig were analyzed by PCR-SSCP technology. Utilizing computer network technique and biological message means, the characteristics of myostatin gene coding region sequences were analyzed comparatively between Tibetan pig and other breeds or species from GenBank. The results accumulated datas for analysing entirely Tibetan pig's heredity resource, and provided theoretic gists for utilizing reasonly Tibetan pig's excellent heredity resource.The research results showed that there was a polymorphism site in exonl in Tibetan pig, and the frequence of AA, AC and CC genotypes were 20.54%, 52.68%, 26.78%, respectively. The frequency of allele A and B were 46.88% and 53.12%. Through comparing the sequencing results with pig myostatin gene relevant sequence (GenBank accession number, AY208121), the Tibetan pig myostatin gene complete coding region sequence (1128bp) was abtained firstly. The sequence was submitted to GenBank under accession number EF612791. The content of A, T, G and C were 32.8%, 25.3%, 21.1%, 20.8%, respectively. GC base (41.9%) was lower than AT (58.1%). One single nucleotide mutation (A→C) in 71bp of coding region in Tibetan pig was found, and this mutation resulted in 24th amino acid change (Asn→Thr).The analysis of myostatin gene coding region sequences between Tibetan pig and other breeds indicated that the difference of base contents were unconspicuous. The nucleotide diversity was 0.00197, and the average number of nucleotide differences was 2.222 in breeds. The mutation of myostatin gene in 71bp was exclusive for Tibetan pig. The contents of twenty kinds of amino acid coding myostatin gene in Tibetan pig were unbalanced. Leucine was the most; histidine and tryptophan were the least. According to the polarity, the content of polarity amino acid was higher than nopolarity amino acid. The usage of synonymous codon was very biased in Tibetan pig, and the similar phenomenons were represented in other breeds.The analysis of myostatin gene coding region sequences between Tibetan pig and other species showed that the similarity between Tibetan pig and other lactation animals were above 90% all. The similarity between Tibetan pig and chicken, salmon were 83.0%, 56.2%, respectively. The analysis of codon usage indicated that the usage of synonymous codon was very biased, and the biased sorts were different among species. Phylogenetic tree of myostatin gene established by neighbor-joining method showed that Tibetan pig and other lactation animals assembled together, moreover, chicken and samlon assembled on other two branches, so the results were in accordance with traditional taxonomy in biology.