[目的]为分析金昌地区西门塔尔牛 MSTN 基因三个外显子的遗传多态性及变异特征。[方法]采用 PCR-SSCP 方法检测了61头西门塔尔牛 MSTN 基因三个外显子的多态性。[结果]显示：金昌西门塔尔牛 MSTN 基因的第1外显子存在 A、B 两个等位基因以及AA、AB 两种基因型，其基因型频率分别为0.7705和0.2295；第2外显子存在 A、B 两个等位基因以及 AA、AB、BB 三种基因型，其基因型频率分别为0.0328、0.3443和0.6229；第3外显子只有 AA 一种基因型。序列分析表明，金昌地区的西门塔尔牛 MSTN 基因第1外显子在269bp 发生了 A→G 的突变和第2外显子在41bp 发生了 C→T 的突变，但都未导致氨基酸发生改变，属于同义突变；外显子3并未检测到突变。[结论]统计结果表明，金昌地区的西门塔尔牛 MSTN 基因第1外显子呈低度多态，第2外显子呈中度多态。%Objective]In order to study the polymorphism in three exons within the MSTN gene in 61 Simmental cattle from Jinchang of Gansu province.[Method]DNA fragment containing the three exons within MSTN gene was amplified and genotyped using PCR single-strand conformation polymorphism (SS-CP)method.[Result]The results showed that the polymorphism in the exon 1 was controlled by A and B alleles that formed two genotypes,namely,AA and AB which possessed the frequencies at 0.7705 and 0. 2295,respectively.The polymorphism of exon 2 was controlled by A and B alleles,that formed three gen-otypes (AA,AB and BB)which possessed the frequencies at 0.0328,0.3443 and 0.6229,respectively. The polymorphism of exon 3 was controlled only by A allele which formed only one genotype (AA).Se-quence analysis indicated that there were two single nucleotide mutations including C to T at 41st nucleo-tide and A to G at 269th nucleotide in exon 2 and exon 1,respectively.Amino acid changes did not occur. However,there was no polymorphism in exon 3.[Conclusion]The overall results showed that the exon 1 had a low level of genetic diversity,while the exon 2 had moderate level of genetic diversity in Simmental cattle from Jinchang of Gansu province.
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