大额牛溶菌酶(LYZ)基因序列测定和进化分析

Sequenceing and Evolution Analysis of the Lysozyme Gene in Mithum(Bos frontalis)

[目的]为了对大额牛与其他物种间分子系统进化研究以及为大额牛群体遗传资源评价、保护与开发利用提供理论依据。[方法]本研究依据普通牛溶菌酶(lysozyme,LYZ)基因已知序列设计引物,用PCR的方法扩增并测定了大额牛LYZ基因的编码区核苷酸序列(444bp),并与GenBank上8个物种相应基因编码区核苷酸序列进行比对分析。[结果]大额牛与普通牛、人、猪、家鼠、沟鼠、猊猴、鸡、斑马鱼各物种在LYZ基因编码区核苷酸序列上同源性大小分别为99.3%、76.6%、79.4%、81.8%、71.3%、68.2%、58.9%、50.5%,并分别采用邻接法(NJ)和最大简约法(MP)构建了大额牛与其他物种间分子进化树,并得到了基本一致的拓扑结构。系统发育分析发现大额牛与普通牛首先聚为一类,再与其他物种聚为一类。该系统聚类结果与动物学分类一致,表明LYZ基因适合于构建不同物种间系统进化树。[结论]本研究为进一步探索大额牛与近缘物种间分子进化,阐明大额牛的真正起源奠定一定实验基础。

[Objective]In order to study the molecular evolution between Mithum and other spieees, to provide theoretical basis of evaluating, protecting and exploiting the Mithum population genetic resource. [Method] Primers designed according to the sequences of Lysozyme gene were used to amplify the nueleo- tide sequence of coding region （444 bp） of Lysozyme gene in Mithum, and the corresponding nucleotide sequences of coding region of eight species retrieved from the GenBank were compared. [Result]The Lyso- zyme gene homologies of the coding region between Mithum and cattle, pig, human, monkey, house mouse, Norway rat, ehicken and zebrafish were 99. 3%, 76. 6%, 79. 4%, 81. 8%, 71. 3%, 68. 2%, 58.9%, 50.5% respectively. The phylogenetie trees were constructed by NJ and MP methods, respectively, and got almost the same topology. The phylogeny analysis showed that Mithum and cattle clustered first, then gathered with other species. The phylogenetic clustering result was identical to the zoological classification system, indicating that the Lysozyme gene were also fit to construct molecular phylogenetic tree among different species. [Conclusion]The study provided an experimental foundation for further studying molecular evolution between Mithum and close relationship species and interpreting really origin of Mithum.