中国牛亚科家畜GH基因编码区序列的遗传变异研究  

Variation of Complete Coding Sequence of GH Gene in Chinese Bovinae Species

作　　者：耿荣庆[1,2] 常洪[2] 李永红[2] 冀德君[2] 常春芳[2] 王兰萍[1] 常国斌[2] 

机构地区：[1]盐城师范学院生命科学与技术学院,盐城224051 [2]扬州大学动物科学与技术学院,扬州225009

出　　处：《畜牧兽医学报》2008年第12期1779-1784,共6页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家自然科学基金(30571323);江苏省高校自然科学基础研究项目(08KJ230002)

摘　　要：采用PCR产物直接双向测序法，分段扩增普通牛、瘤牛、牦牛、大额牛和亚洲水牛共5个牛种的GH基因，并拼接成编码区全序列，分析中国牛亚科家畜不同牛种GH基因编码区序列变异及其分子进化特征。结果表明，牛GH基因编码区序列全长654bp，种间核苷酸突变率在0．1％～1．84％。5个牛种编码区序列定义了10种单倍型，瘤牛的单倍型多样性最高，大额牛和水牛均无单倍型多样性。GH基因编码区序列的密码子使用存在偏倚性，共发现了25个偏好性密码子。核苷酸的替代以转换为主，转换明显高于颠换，转换／颠换比为3．0。非同义突变位点远远少于同义突变位点，同义与非同义替代发生的速率比都小于或等于1，表明GH基因编码区序列不受达尔文正选择的影响。以GH基因单倍型序列为基础的分子进化树表明，水牛与普通牛、瘤牛、牦牛、大额牛间分化很明显；普通牛、瘤牛、牦牛、大额牛间序列分化并不明显，并且它们共同拥有一条相同的祖先核苷酸序列。说明中国牛亚科家畜GH基因编码区序列的变异相当贫乏，并且由于功能的约束表现得相当保守，进化速率相当缓慢。CDS of GH gene of 5 bovine species Bos taurus, Bos indicus , Bos grunniens , Bos frontalis and Bubalus bubalis was connected from PCR fragments by standard double-strand DNA sequencing method to analyze the variation and molecular evolution of complete coding sequence （CDS） of growth hormone （GH） gene in Chinese bovinae species. The result showed that CDS of GH gene was 654 bp in length and mutation rate was between 0. 1% and 1.84% of different bo- vine species. Total 10 haplotypes were defined according to sequences. Bos indicus possessed the highest haplotype diversity and no haplotype diversity was observed in Bos frontalis and Bubalus bubalis. There was codon usage bias in CDS and 25 preferenced codon were discovered. The predominant substitution model of nucleotide was transition and transition was higher than transversion with the ratio of 3.0. Nonsynonymous sites were far less than synonymous sites. The ratio of synonymous and nonsynonymous substitution were all less or equal to one manifesting that it was not effected by Darwin positive selection. Molecular tree based on haplotype of GH sequence showed that differentiation was very apparent between Bubalus bubalis and Bos taurus, Bos indicus , Bos grunniens , Bos frontalis. There was no apparent differentiation among Bos taurus, Bos indicus, Bos grunniens, Bos frontalis and they shared an alike ancestral sequence. CDS of GH gene in Chinese bovinae species was fairly conservative under functional constraint during the course of evolution together with few variation and low evolution velocity.

关 键 词：牛亚科 生长激素基因 编码区序列 分子进化 

分 类 号：S823.2[农业科学—畜牧学]