Abstract: Objective To study the homology of MHC-DRB3.2 gene in human beings and some laboratory animals.Methods Cattle genomic DNA was used as the template to amplify DRB3.2 gene fragment by PCR and the products of PCR were sequenced.The DRB3.2 gene fragment of other laboratory animals,including human beings,macaque,sheep,goat and swine were down loaded from GenBank,and base compositions,homology and molecular evolution trees were analysis by DNAMAN software.Results DRB3.2 gene fragment in all those species mentioned above were 267 base pairs and the gene hasn't any deletion or insertion.There is no significant difference in the base contents of A,T,G,C and G+C among those animal species.As for certain special animal,the content of G was the highest and T was the lowest,the content of G+C was obviously higher than that of A+T.The homology between human beings and macaque,sheep,goat,cattle and swine were 91.8%,82.8%,82.4%,81.3% and 81.6%,respectively.Conclusion The nucleotide sequence homology of DRB3.2 gene shares a high sequence identity in different species;macaque plays a very important role in studies of human diseases,and it could not be replaced by other laboratory animals.DRB3.2 gene is an ideal genetic marker for organic evolution and phylogeny analysis.

Key words: MHC, DRB3.2 gene, Nucleotide sequences, Homology analysis

摘要： 目的研究人类及部分实验动物DRB3.2基因核苷酸序列的同源性。方法利用PCR技术扩增得到牛的DRB3.2基因片段,并测定其核苷酸序列;从GenBank中下载人类、猕猴、绵羊、山羊、猪的相应基因片段;利用DNAMAN软件进行碱基组成分析、同源性分析和构建分子进化树。结果所分析的物种该基因片段大小为267bp,没有发现碱基的缺失以及插入现象;A、T、G、C四种碱基以及G+C的含量在不同物种之间相差较小。就某种动物来说,G的含量最高,T的含量最低,G+C的含量要明显高于A+T含量;人类与猕猴、绵羊、山羊、牛、猪的同源性分别为91.8%、82.8%、82.4%、81.3%、81.6%。结论不同物种MHC-DRB3.2基因核苷酸序列的同源性都比较高;在研究人类有些疾病时,猕猴是其它实验动物不可替代的;DRB3.2基因是研究生物进化和系统发育分析的一个理想遗传标记。

关键词: MHC, DRB3.2基因, 核苷酸序列, 同源性分析