Research On Mitochondrial Genome Of Orientobilharzia Turkestanicum

Orientobilharzia turkestanicum, which belongs to Platyhelminthes, Trematoda, Digenea, Schistosomatidae, Schistosomatinae, and Orientobilharzia. Adult worms of O.turkestanicum live in the portal veins or intestinal veins of cattle, sheep and other animals and cause orientobilharziasis, which have an important impact on livestock industry and have a large distribution in Asia and several areas of Europe. In the past, research on Orientobilharzia turkestanicum and orientobilharziasis were mainly focus on the epidemiology, diagnosis, treatment and prevention. However, little has been done for the classification and molecular phylogeny of O. turkestanicum recently. Mitochondrial DNA (mtDNA) is genetic material out of the nucleus of metazoan organisms. Mitochondrial genome sequences provide useful markers for investigating population genetic structures, systematics and phylogenetics because of their maternal inheritance, high evolutionary rates, small size and simple structure. The studies on mitochondrial genomes are one of the most essential parts in recent molecular biology. The objectives of the present study were to determine the gene order, composition, codon usage pattern, translation initiation/termination codons of the mt genome of O. turkestanicum and to compare with other schistosomes, and examine the phylogenetic relationships of O. turkestanicum with members of the schistosomes using comparative mt genomics.Genomic DNA was extracted from ten individual parasite isolated from sheep by SDS-proteinase K method. All genes were amplified by PCR and cloned into pMD18-T easy vector and then sequenced and compared with Chromas and DNASTAR software, and the phylogenetic analyses of mitochondrial genome were analyzed by Maximum Likelihood method and neighbor-joining method. The results showed that the complete genome sequence length 14754bp and comprises genes encoding: 12 proteins (cytochrome c oxidase subunits 1–3 [cox1-3], cytochrome b [cytb], subunits 6 of the adenosine triphosphatase complex [atp6] and the seven subunits of the nicotinamide dehydrogenase complex [nad1-6 and nad4L]), the large and small subunits of ribosomal RNA (also known as 16S and 12S or designated rrnL and rrnS, respectively) and 22 tRNAs. Using Taenia pisiformis as outgroup, reconstruction of the phylogenetic relationship of trematoda. The result showed that blood fluke clearly divided into two evolutionary branch, one contains S.mansoni, S.spindale and S.haematobium; the other contains S.japonicum, S.mekongi and S.malayensis. O. turkestanicum should be within Schistosoma genus and closed the former.