Genetic diversity of the Chinese liver fluke Clonorchis sinensis from Russia and Vietnam

• Published in: International journal for parasitology 2014-10, Vol.44 (11), p.795-810
• Main Authors: Chelomina, Galina N., Tatonova, Yulia V., Hung, Nguyen Manh, Ngo, Ha Duy
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Clonorchiasis - epidemiology; Clonorchiasis - parasitology; Clonorchis sinensis; Clonorchis sinensis - genetics; COX1; cox1 gene; DNA, Helminth - genetics; Genetic diversity; Genetic Variation; Intraspecific phylogeny; Male; Phylogeny; Rats; Rats, Sprague-Dawley; Russia - epidemiology; Vietnam - epidemiology
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/j.ijpara.2014.06.009

•Low nucleotide and high haplotype differentiation was revealed in Russian and Vietnamese samples of Clonorchis sinensis.•A clear northward direction was detected for haplotype frequencies and pattern of nucleotide diversity along the cox1 gene.•There are several region-specific phylogenetic lineages which could have occurred in the penultimate Pleistocene glaciation.•The results suggest a deep local adaptation of the fluke and population growth with no bottleneck in the late Pleistocene.•The data promote understanding of species phylogeography, parasite-host interactions and epidemiology of clonorchiasis. Clonorchiasis is a parasitic disease of high public health importance in many countries in southeastern Asia and is caused by the Chinese liver fluke Clonorchis sinensis. However, the genetic structure and demographic history of its populations has not been sufficiently studied throughout the geographic range of the species and available data are based mainly on partial gene sequencing. In this study, we explored the genetic diversity of the complete 1560bp cytochrome c oxidase subunit 1 (cox1) gene sequence for geographically isolated C. sinensis populations in Russia and Vietnam, to our knowledge for the first time. The results demonstrated low nucleotide and high haplotype differentiation within and between the two compared regions and a clear geographical vector for the distribution of genetic diversity patterns among the studied populations. These results suggest a deep local adaptation of the parasite to its environment including intermediate hosts and the existence of gene flow across the species’ range. Additionally, we have predicted an amino acid substitution in the functional site of the COX1 protein among the Vietnamese populations, which were reported to be difficult to treat with praziquantel. The haplotype networks consisted of several region-specific phylogenetic lineages, the formation of which could have occurred during the most extensive penultimate glaciations in the Pleistocene Epoch. The patterns of genetic diversity and demographics are consistent with population growth of the liver fluke in the late Pleistocene following the Last Glacial Maximum, indicating the lack of a population bottleneck during the recent past in the species’ history. The data obtained have important implications for understanding the phylogeography of C. sinensis, its host-parasite interactions, the ability of this parasite to evolve drug resistance, and the