牦牛MSTN基因内含子Ⅱ遗传多样性研究

Analysis on Single Nucleotide Polymorphisms on Intron2 of MSTN Gene in Five Yak Breeds

利用PCR-SSCP技术研究了5个牦牛群体共计401头个体的MSTN基因第2内含子的多态性。结果表明:牦牛MSTN基因第2内含子存在多态性,测序发现该片段第192 bp处有一个A到G的单碱基突变。所检测的5个牦牛群体中,除新疆巴州牦牛群体未检测到AA基因型,其他4个群体中均发现AA、AB和BB 3种基因型,大通牦牛、甘南牦牛、青海高原牦牛群体中均以BB型为优势基因型,而天祝白牦牛和新疆巴州牦牛则以AB为优势基因型。不同牦牛群体中均检测到A,B两个等位基因,并且B基因频率均高于A基因频率,B等位基因为各牦牛群体中的优势等位基因。各群体经过χ2检验,在该基因座上,甘南牦牛、天祝白牦牛、青海高原牦牛3个群体处于Hardy-Weinberg平衡状态(P>0.05),大通牦牛、新疆巴州牦牛两个群体处于不平衡状态(P<0.05)。分析了5个牦牛群体的遗传结构,发现大通牦牛的基因杂合度、有效等位基因数、多态信息含量等均最低,分别为:0.171,1.207,0.157;而天祝白牦牛的基因杂合度,有效等位基因数、多态信息含量等均最高,分别为:0.490,1.961,0.370;新疆巴州牦牛的基因杂合度、有效等位基因数、多态信息含量等均略低于天祝白牦牛。

The polymorphisms on intron2 of MSTN gene of 401 individules in five yak breed were studied by PCR-SSCP assay.The results indicated that the amplified products have polymorphism.Sequencing revealed a A→G mutation at 192 bp on intron2 of MSTN gene in yak.Three genotypes containing AA,AB and BB were all detected in these yak breeds except that no AA genotype was presented in individuals of Bazhou yak.BB genotype was dominance ones in groups of Datong,Gannan and Qinghai highland yak while AB genotype was dominance in those of Tianzhu White yak and Bazhou yak. Alleles A and B were present in every observed yak breed and the allele B was in majority. For Gannan, Tianzhu White yak and Qinghai highland yaks, they were in Hardy-Weinberg equilibrium state, while obviously they were not in Hardy-Weinberg equilibrium state in Datong and Bazhou yak groups in the locus region by X2 test analysis. The resuits of heredity study on five yak breeds showed that the gene heterozygosis, allelomorphic gene and polymorphism in Datong new breeds was 0. 171,1.207 and 0. 157,respectively. And those in Tianzhu White yak was 0.490,1.961 and 0. 370,respectively. And those in Bazhou yak was lower than Tianzhu White yak.