甘肃武威西门塔尔牛MSTN基因外显子遗传变异的研究

为分析肉牛MSTN基因的遗传多态性及变异特征，采用PCR-SSCP方法检测了60头甘肃武威西门塔尔牛MSTN基因的多态性，对群体内各等位基因进行了克隆测序。结果显示：武威西门塔尔牛MSTN基因第1外显子存在A、B两个等位基因以及AA、AB两种基因型，基因型频率分别为0.9167、0.0833；第2外显子存在A、B两个等位基因以及AA、BB、AB三种基因型，基因型频率分别为0.5、0.25、0.25。序列分析表明，武威西门塔尔牛MSTN第1外显子在269 bp发生了A→G的突变，第2外显子在41 bp发生了C→T的突变，二者均属于同义突变。统计结果表明，武威西门塔尔牛MSTN基因第1外显子呈低度多态，第2外显子呈中度多态，外显子3没有发生突变。

Polymorphism in Exons of MSTN Gene in Wuwei Simmental

In order to study the polymorphism and variation in exons of MSTN gene in 60 Wuwei Simmental.DNA fragment containing the exons of MSTN gene was amplified and genotyped using PCR single-strand conformational polymorphism（SSCP） method. Representative alleles were sequenced by cloning for verification of their variations in DNA sequences.The results showed that the polymorphism in the exon 1 was controlled by A and B alleles which formed two genotypes namely AA and AB with frequencies at 0.916 7 and 0.083 3 respectively;that the polymorphism in the exon 2 was controlled by A and B alleles which formed three genotypes namely AA,BB and AB with frequencies at 0.5,0.25 and 0.25 respectively;that the polymorphism in the exon 3 was only controlled by A allele which formed one genotypes namely AA. Sequence analysis indicated that there was a single nucleotide mutation including A to G at 269th nucleotide in the exon land a single nucleotide mutation including C to T at 41th nucleotide in the exon 2,but no amino acid change;that there was no nucleotide mutation in the exon 3.The overall results showed that exon 1 of MSTN gene had a low level of genetic diversity in Wuwei Simmental;that exon 2 of MSTN gene had a middle level of genetic diversity in Wuwei Simmental.