Abstract
Echinococcus granulosus is the etiological agent of cystic echinococcosis, a major zoonotic disease of both humans and animals. In this study, we assessed genetic variability and genetic structure of E. granulosus in the Tibet plateau, using the complete mitochondrial 16 S ribosomal RNA gene for the first time. We collected and sequenced 62 isolates of E. granulosus from 3 populations in the Tibet plateau. A BLAST analysis indicated that 61 isolates belonged to E. granulosus sensu stricto (genotypes G1–G3), while one isolate belonged to E. canadensis (genotype G6). We detected 16 haplotypes with a haplotype network revealing a star-like expansion, with the most common haplotype occupying the center of the network. Haplotype diversity and nucleotide diversity were low, while negative values were observed for Tajima's D and Fu’s Fs. AMOVA results and Fst values revealed that the three geographic populations were not genetically differentiated. Our results suggest that a population bottleneck or population expansion has occurred in the past, and that this explains the low genetic variability of E. granulosus in the Tibet Plateau.
Acknowledgements
The authors thank Ning Yan and Tianyu Liu for their helpful assistance in performing the experiments; and we would like to express our gratitude to Deying Yang and Lin Chen for their assistance in analyzing the data and collecting samples, respectively.
Declaration of interest
No competing financial interests exist. The authors alone are responsible for the content and writing of the article. This work was supported by grants from the National Key Technology R&D Program of China (No. 2006BAI06B09); and the Science and Technology Projects from General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China (No. 2009IK019).