First description of genetic diversity for the genus Metagonimus using the complete cox1 gene sequence

The complete cox1 gene sequence was analysed for Metagonimus suifunensis from eight localities in the Russian southern Far East, and the level of variability was compared with that of Clonorchis sinensis from the same territory of Russia. These species belong to the superfamily Opisthorchioidea, have a similar distribution in the Russian southern Far East and share second intermediate and definitive hosts, but are distinguished by their first intermediate hosts belonging to different orders of caenogastropods. The data obtained showed that the nucleotide sequence variability of the M. suifunensis cox1 gene was significantly lower. This fact is considered in connection with a recent bottleneck passage for the M. suifunensis population, in contrast to C. sinensis, which could be due to the features of the Metagonimus life cycle under seasonal freezing temperatures, as well as historical geological and climatic changes in the Russian Far East. These factors could influence the microevolutionary processes and lead to a decrease in the level of variability in the M. suifunensis population. Based on the combination of genetic data and historical geo-processes in the region, the probable route of M. suifunensis expansion from the northern part of its current area in the Amur River basin to the southern territories of the Russian Far East is justified.