黑线仓鼠MHCⅡ类DQA基因外显子2的克隆与序列分析

为了探明黑线仓鼠MHC的结构与功能并寻找分子标记，对MHCⅡ类DQA基因的外显子2进行克隆和序列分析．提取黑线仓鼠3个群体（吴村、沂南和临朐）的基因组DNA构建基因池，利用PCR技术扩增得到249bp的片段，将该目的片段连接到pMD18-T载体中，重组质粒转入大肠杆菌DH5α后利用蓝白斑法筛选阳性克隆，测序后得到该目的片段的核苷酸序列（Genbank登录号：FJ209306）并推导出氨基酸序列．结果表明：黑线仓鼠、人类、大鼠、小鼠、猪、马、牛、兔之间DQA基因外显子2的核苷酸序列同源性为68．7％-85％，氨基酸序列同源性为56．8％-83．5％，黑线仓鼠与大鼠、小鼠亲缘关系更近．测序得到的OQA基因外显子2的序列在物种间具有丰富的多态性，可以作为物种遗传分析的分子标记．

Cloning and Sequence Analysis of MHCⅡ Exon 2 of DQA Gene in Cricetulus Barabensis

In order to research the structure and ruction of MHC in Cricetulus Barabensis and look for a specific DNA marker, the genomic DNA is abstracted from three populations- Wucun, Yinan and Linqu, Shandong province, China. The 249 bp fragment of exon 2 of DQA gene is amplified successfully by PCR and cloned into pMD18- T vector, it the recombined carriers into E. coli DH5α after recombination. The positive clones are further identified by PCR. The nucleotide sequence of this fragment is acquired and the peptide sequence is deduced. The Genbank number for the former sequence is FJ209306. Homologies of nucleotide sequence and amino acid sequence of exon 2 among Cricetulus Barabensis, human, rat, mouse, pig, horse, cattle and rabbit are from 68.7% to 85% and from 56.8% to 83.5%, respectively. So Cricetulus Barabensis is more similar to rat and mouse. This fragment is very polymorphie and can be used as a molecular marker for genetic analysis among species.