MOLECULAR IDENTIFICATION AND PHYLOGENETIC STUDY OF LIGULA INTESTINALIS PLEROCEROID IN GYMNOCYPRIS PRZEWALSKII FROM THE QINGHAI LAKE, CHINA

To identify Ligula intestinalis pleroceroid parasitizing in the abdominal cavity of Gymnocypris przewalskii and analyze its phylogenic status from Qinghai Lake, China, polymerase chain reaction (PCR) of 18S ribosomal RNA gene, COⅠand COB gene was carried out. Their sequences homologies with other tapeworm species were analyzed and the phylogenetic relationships were inferred. The results showed that the noodle-like parasite was identified as L. intestinalis, and that its 18S rRNA gene homogeneity was 100.00% with AF254121 (China), and COⅠand COB gene homogeneities were 99.49% and 93.32% with AF153910 (China) and JQ279109 (Algeria), respectively. Furthermore, the phylogenetic trees based on the 18S rRNA, COⅠand COB gene sequences indicated that the collected tapeworm was in the same branch with L. intestinalis, which are close to the isolated species from China. The phylogenetic relationship between the identified L. intestinalis and other tapeworm species was elucidated.