Abstract: The objectives of the present study were to amplify and analyse the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene among D.chinensis isolates from Gansu province in China, and to study its phylogenetic relationships with trematodes of the other families using cox1 gene sequence. The partial cox1 (pcox1) were amplified from each D.chinensis sample, and pcox1 sequences were aligned using the Clustal X 1.81. Maximum parsimony (MP) and maximum likelihood (ML) trees were constructed using the software Phylip 3.67 version 4.0, and ML tree was also constructed using Puzzle version 5.2. The lengths of all the pcox1 sequences were 355 bp. Phylogenetic analyses showed that the D.chinensis samples from Gansu were clustered in the same clade. The present study reported the mitochondrial cox1 sequence of D.chinensis for the first time. The results of this study provided foundation for further studies on molecular genetics and diagnostics of D.chinensis.

Key words: D.chinensis; mitochondrial DNA; cox1 gene; relationship