SARS冠状病毒基因溯源分子生物信息学分析

目的：对广东省两次流行的SARS冠状病毒（SARS—CoV）进行分子水平的溯源分析，为进一步研究SARS冠状病毒提供分子生物信息学资料。方法：对GenBank登录的SARS冠状病毒和SARS样冠状病毒（SARS—like CoV）核酸序列进行了分析，以Breda病毒为外组，构建了SARS冠状病毒和SARS样冠状病毒系统进化树，并进行单核苷酸变异分析。结果：发现两次SARS自然流行的病毒可分为两个明显不同的聚类；第二次流行时从人类中分离的SARS冠状病毒和从果子狸等动物中分离的SARS样冠状病毒可分为两个基因型，两型的主要鉴别依据是病毒的全基因组变异而非Spike基因序列。结论：前后两次SARS自然流行病毒可能以不同的特性感染人类而不是简单的重复。结合流行病学资料，对第二次流行时的SARS冠状病毒进行分子水平溯源分析的结果表明，分离自前2例指标患者的病毒基因序列与来自果子狸等动物的SARS样冠状病毒的基因序列存在较大的差异。提示第二次流行的SARS冠状病毒由果子狸等动物传染人的论据不足。

Molecular bioinformatic analysis of gene on SARS-CoV by being traced to source

Objective:We carred on molecular level analysis on severe acute respiratory syndrome coronavirus(SARS-CoV) which produced twice natural epidemic of SARS in Guangdong province by traced to the source to provide information for studies the SARS-CoV deeply.Methods:We analyzed nucleic acid sequence of the SARS-CoV and SARS-like CoV which were obtained from the GeneBank.The evolutionary trees of SARS-CoV and SARS-like CoV were made up by using the Brede virus as outgroup,and analyzed variation in single nucleotide sequence.Results:We discovered that the SARS-CoV of twice natural epidemic which may be classified two obvious different clusterings.When the SARS spreded the second time,the SARS-CoV from human and the SARS-like CoV from civet cats may be classified two genetypes.The main distinguishing bases between two genetypes is variation in the whole genome but not the Spike gene sequence.Conclusion:It is possible that the SARS-CoV which produced twice natural epidemic of SARS infected human by different characters but not simple repetition.To combine epidemiology information,results which we analyzed the SARSCoV of the second epidemic in molecular level by traced to the source indicates that there are larger difference between gene sequence of the SARS-CoV from the front 2 case target suffers and gene sequence of the SARS-like CoV from civet cats.It is not yet sure whether the SARS-CoV of the second epidemic is caused by civet cats or not.