采用磁性分离技术从登革热病毒 (D2 0 4株 )感染的C6/36细胞中分离了D2 0 4病毒RNA .以该RNA为模板进行RT PCR ,分别扩增了D2 0 4RNA 5′和 3′端cDNA片段 ,该cDNA片段分别克隆到 pGEM 3Z质粒多聚接头的HincⅡ位点得到含有 5′端 2 84bp及 3′端 52 5bpcDNA的重组质粒 .通过荧光标记引物及双脱氧核苷酸PCR方法测定了上述cDNA插入片段的序列 .同源性比较结果证明D2 0 4株与其他不同株间的同源性较高 ,可达 93%～ 98% ;不同型间的同源性较差 ,仅 80 %左右 ;属间的同源性更低 D2 0 4 viral RNA was isolated from C6 / 36 cells infected with dengue virus (D2 0 4) using magnetic isolation technique, and RT PCR was performed using this RNA as a template to amplify the 5 ’and 3’ ends of D2 0 4 RNA cDNA fragment was cloned into the Hinc Ⅱ site of the polylinker of pGEM 3Z plasmid to obtain a recombinant plasmid containing 5 ’end of 2 84 bp and 3’ end of 52 5bp cDNA.According to fluorescent labeled primer and dideoxynucleotide PCR method, The results of homology comparison showed that the homology between D2 0 4 strain and other different strains was high, reaching 93% -98%. The homology between different types was poor, only 80% Around; lower homology between the genus