Objective To determine the phylogenetic position of Schistosoma sinensium in the genus Schistosoma using mitochondrial cytochrome C oxidase 1 (CO1) and NADH dehydrogenase 1(ND1) as molecular markers. Methods The genomic DNA of adult worms were extracted by the GNT\|K method. The target regions were amplified by PCR using specific primers. The PCR products were purified before ligation into the plasmid Zero\|Blunt. Recombinant plasmids were amplified in E.coli, extracted and purified using routine methods and then sequenced using M13 primers (F/R) on a Licor long\|read auto\|sequencer. Sequences of related schistosomes were retrieved from GenBank and aligned with our data in the sequence editor ESEE. Gene trees were constructed in PHYLIP and MEGA using both maximum parsimony and neighbor\|joining methods. For parsimony analysis, all characters were treated as unordered and with equal weights. At least \{3 000\} cycles of bootstrapping were carried out. For analysis in MEGA, all gap columns were deleted. The third position of codon was included. Results The nucleotide and amino acid sequences of CO1 and ND1 of S.sinensium were obtained. Conclusion The phylogenetic trees from these molecular data suggested that S.sinensium belongs to the Asian schistosome group, and the results coincided with the previous rDNA (ITS2 & LSU) analysis results.

Objective To classify the taxonomic status of O.cheni in relation to O.turkestanicum var. tuberculata from the mainland of China by comparing their nucleotide sequences of nuclear ribosomal partial large subunit gene (LSU). Methods The genomic DNA of adult worms were extracted by the GNT-K method. The target gene was amplified by PCR using specific primers. The PCR products were purified before ligation into the plasmid PCR-blunt (Invitrogen). Recombinant plasmids were amplified in E.coli , extracted and purified using routine methods and then sequenced using M13 primers (F/R) on a Licor long-read auto-sequencer. Sequences of O. turkestanicum was retrieved from GenBank and aligned with our data in BioEdit. Results The nucleotide sequences of LSU between O.turkestanicum var. tuberculata and O.cheni was 100% identical, and 99.99% identical between O.turkestanicum var. tuberculata and O.turkestanicum . Conclusion This study demonstrated high similarity in LSU nucleotide sequences, and the results do not support O.cheni as an independent species. O.cheni may be a synonym of O.turkestanicum var. tuberculata , and O.turkestanicum var. tuberculata is probably also a synonym of O.turkestanicum .

Objective To study the mitochondrial cytochrome C oxidase 1(CO1) gene of Oncomelania snails from Miao River area in Hubei Province.Methods Oncomelania snails were collected from Miao River area, including upstream and downstream. Genomic DNA was extracted from the tissue of the snail. PCR was used to amplify a fragment of the CO1 gene. Sequences of the CO1 fragment were determined directly from the purified PCR products by an automated sequencer. Sequences for each individual were assembled and edited using ESEE 3 0 s. A distance matrix was computed using program DNADIST of PHYLIP(3 57). Unrooted maximum likelihood trees were calculated from program FITCH.Results The amplified CO1 gene of the snail was a fragment of 638 bp in length. Sequence analysis showed that the accumulated variable sites were significant different between upstream and downstream populations, being 29 and 46, respectively. From the number of variable sites in the gene,snails in this area were roughly separated into two groups. Each of them was a mixture of both upstream and downstream snails.Same haplotypes were confirmed to be present among the collected sites along the river. From the distance matrix of sequence divergence, the population upstream vs downstream differed by 0 0221?0 0105.Conclusion There were more variation in downstream population than that in upstream.Gene flow was identified in these populations. The phylogenetic trees suggest the existence of two groups,but all of them belong to O h hupensis .