[Cloning and sequence analysis of ITS gene of Leishmania donovani isolates from different epidemic foci in China].

This study was directed to determine the nucleotide sequence of the ITS (internal transcribed spacer) gene of Leishmania donovani isolates from desert foci (L. d XJ771), hill foci (L. d SC10) and plain foci (L. d SD2), and to find out the differences of the sequences of ITS gene among these three isolates. The specific ITS fragments from nuclear DNA of three Leishmania isolates were amplified by PCR, cloned into PMD18-T vector, and then sequenced by the dideoxy chain termination method. Sequence analysis showed that the amplified DNA fragments of the three isolates were 1 086 bp (L. d XJ771), 1 027 bp (L. d SC10) and 1 028 bp (L. d SD2). There were obvious sequence differences among L. d XJ771, L. d SC10 and L. d SD2. The differences between L. d XJ771 (desert foci isolate) and L. d SC10 (hill foci isolate) were less than the differences between L. d XJ771 (desert foci isolate ) and L. d SD2. (plain foci isolate).