Sequences of internal transcribed spacers and two mitochondrial genes: Effective genetic markers for Metorchis orientalis

Abstract

The present study examined sequence variations in the Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA) and two mitochondrial DNA (mfDNA) regions, namely cytochromec oxidase subunit 1 (coxl), NADH dehydrogenase subunits 1 (nadl), among Metorchis orientalis metacercaria isolates from Guangxi in China. The sequences of ITS, pcoxl and pnadl were amplified from 6 individual M. orientalis metacercariae and sequenced. The relevant sequences of other 7 trematode species belonging to 6 genera in 4 families were downloaded from GenBank and their phylogenetic relationships were re-constructed using the combined pcoxl and pnadl mt DNA sequences with Trichinella spiralis as outgroup. The results showed that sequences of ITS rDNA, pcoxl and pnadl of M. orientalis were 1131, 654 and 650 bp, respectively and they were quite conserved among the M. orientalis isolates. However, they were quite different from that of other species, phylogenetic analysis of the combined pcoxl and pnadl mt DNA sequences were able to distinguish M. orientalii from different species of the Opisthorchiidae and trematodes in other families. Therefore, the ITS, coxl and nadl mtDNA sequences provide effective genetic markers for the specific identification of trematodes of the Opisthorchiidae family and have implications for studying their population biology, genetic structure, as well as molecular epidemiology. © Medwell Journals, 2010.