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 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.