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目的了解甲型肝炎病毒(HAV)在中国几个城市的基因型分布，为HAV的分子流行病学追踪调查提供方 法和依据。方法17株HAV代表株分别来自不同城市的甲型肝炎病人粪便或血清，病毒RNA经蛋白酶K消化、酚/ 氯仿提取和乙醇沉淀后，以逆转录-套式聚合酶链反应(RT-PCR)扩增合成HAVVP1/2A交接区基因区，并 进行直接核苷酸序列分析和差异比较。 结果VP1/2A交接区核苷酸序列分析表明，所有病毒株均从属于基因Ⅰ型；约53％为ⅠB亚型，亚型间差 异小于6％；约47％为ⅠA亚型，亚型间差异小于5.3％；ⅠA与ⅠB亚型间的同源性为88.7％-92.3％。 结论中国流行或散发的HAV株可能有基因ⅠA、ⅠB亚型同时存在，流行病学相关的病毒株核苷酸序列 相同或相近。,Objective To clarify the distribution of hepatitis A virus (HAV)genotype in geographical regions of China. Methods Seventeen representative HAV strains were isolated from the stool or serum of hepatitis A patients in different geographical regions. Viral RNA was recovered from stool or serum by proteinase K digestion and phenol-chloroform extraction, followed by ethanol precipitation prior to reverse transcription and polymerase chain reaction (RT-PCR) amplification. The nucleotide sequences of VP1/2A junction region were tested by using a direct sequencing technique. Results A pairwise comparison of sequences within 168 bases at the VP1/2A junction revealed that all the sequences clustered within genotype Ⅰ. About 53% of strains clustered in genotype ⅠB, with less than 6% variability; while the others clustered in genotype ⅠA, with less than 5.3% variability. Sequence homology between genotype ⅠA and ⅠB varied from 88.7% to 92.3%. Conclusion Epidemic or sporadic HAV strains in China may belong to HAV genotype ⅠA or ⅠB. Epidemiologically related strains may be identical or closely related in sequence.