摘要目的 试验证实我国黑热病不同疫区分离出的5个L.d分离株的小亚基核糖体DNA可变区序列存在点突变.方法将7个利什曼原虫种/株的nDNA进行PCR扩增，将扩增出的SSU rDNA基因的特异片段克隆于pGEMR-T Easy Vector上，采用通用引物M13进行PCR扩增，全自动测序仪测序。结果序列分析显示，扩增的7种/株利什曼原虫SSU rDNA序列大小为392 bp，5个点突变均发生在两个独特序列区（UQ-I和UQ-II）；无移码突变。经与基因库中利什曼原虫序列类似性比较，同源性在98%以上。结论首次报道我国黑热病不同疫区的5个L.d.分离株的SSU rDNA可变区存在5个点突变。

abstractsObjective To confirm the existence of point mutations I n the SSU rDNA variable regions of 5 Leishmania donovani (L-d) isolates from different epidemic foci in ChinaMethods Specific SSU rDNA fragments from nuclear DNA of 7 Leishmania species/isolates were amplified by PCR and then cloned into pGEMR-T Easy Vectors After that, the specific fragments were sequenced by an auto mated DNA sequencerResults Sequence analysis showed that the amplified DNA fragments of 7 Leishmania species/isolates were all 392 bp in length All 5 po int mutations were located in two unique sequence blocks (UQ-Ⅰ and UQ-Ⅱ), a nd no insertions or deletions were found The dentities of comparison of Leish mania in GeneBank were more than 98%.Conclusion Five point mutations exist in the ssu rDNA variable region of 5 L.d.isolates from different epidemic foci of visceral leishmaniasis (VL) in China. Sequence differences differences of the SSU rDNA variable region exist among L.d.isolates from different foci.