中文摘要：

为明确牦牛乳中α-乳白蛋白遗传多样性,以α-乳白蛋白基因（LAA）的Ⅰ、Ⅱ、Ⅲ和IV外显子为研究对象,采用聚合酶链反应-单链构象多态性（PCR-SSCP）方法对麦洼牦牛的LAA进行分析,旨在从分子水平揭示LAA在牦牛乳中遗传多样性分布.牛属不同来源的α-乳白蛋白基因的编码序列被用于构建系统发育树.结果表明,牦牛乳中LAAⅠ外显子区域以杂合体形式存在,并发现了一个新变异体JN084189.不同来源LAA的系统发育树分析表明,LAA在进化上存在一定的物种特异性.

英文摘要：

A polymorphism of α-lactalbumin gene LAA exon Ⅰ,Ⅱ,Ⅲ,and IV has been identified by PCR-single strand conformation polymorphism protocol to reveal the distribution of diversity of α-lactalbumin in Maiwa yak at the molecular level.The sequences corresponding to the coding region of α-lactalbumin gene were used for phylogenetic analysis to establish the phylogenetic relationship of LAA variants in the Bos genus.Experimental results indicated that most yak milks were with hybrid genotype in exon Ⅰof α-lactalbumin.A new variant had been identified in Maiwa yak breed by resquencing analysis and entered into GenBank with accession number JN084189.The phylogenetic analysis presented α-lactalbumin evolution consistent with species at a degree.