Abstract: 　Objective To study genomic diversity among the isolates of Schistosoma japonicum in China. Methods Schistosome adults were collected from different endemic areas. Mitochondrial NADH dehydrogenase 1 (ND1) and cytochrome C oxidase 1 (CO1) gene fragments of the worms were amplified by PCR, cloned into plasmid, and finally sequenced. Program MEGA was used for sequence analysis. Results The ND1 and CO1 genes amplified from different geographic strains were 476 bp and 1 033 bp, respectively. There are two distinct haplotypes,type Ⅰ and Ⅱ, for both ND1 and CO1 nucleotide sequences. The differences between the two types were 4.0% and 3.4%. They are considered to be two different genetypes by the phylogenetic analysis. In individual mitochondrial gene, type Ⅰ of ND1 was fixedly accompanied with type Ⅰ of CO1 gene, and type Ⅱ of ND1 with type Ⅱ of CO1. Conclusion There are two different genetypes of ND1 and CO1 genes of S.japonicum in China.

Key words: Schistosoma japonicum, mitochondrial NADH dehydrogenase 1, cytochrome C oxidase 1, genomic diversity, sequence analysis