COI and ND1 as DNA barcodes to identify Taenia hydatigena (Cestoda: Taeniidae) from canine small intestine on Hainan Island in China

DNA barcoding based on universal gene markers is a fast, accurate, and innovative approach for the molecular discrimination of species. Some species are particularly difficult to discriminate using a traditional morphological identification method because of severely damaged morphological features. In this study, cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 1 (ND1) were used as barcoding markers to distinguish Taenia hydatigena in dogs on the tropical island of Hainan. Therefore, geographic differentiation based on the COI and ND1 sequences amongst the specimens and other geographic isolates in GenBank was determined by calculating the genetic distances according to the Kimura 2-parameter (K2P) model and constructing a phylogenetic tree using the neighbour-joining (NJ) method. Barcoding gap, base composition, and base saturation were tested to assess the effectiveness of the barcoding marker COI and ND1 genes for specimen identification. In addition, we analysed the barcoding gap and saturation and performed molecular evolutionary analysis of the intraspecies and interspecies diversity of Taenia.