[A polymorphism study of the genomic DNA of trematodes at different phases of development]

Polymorphism of the genome DNA in different development stages of trematodes by means of the polymerase chain reaction (PCR) with universal primers was investigated. Interspecific variation in Trichobilharzia ocellata (cercaria) was shown in samples from the Moscow area and some regions in Byelorussia (Naroch Lake). Population groupments of T. ocellata are correlated with migration routes of subpopulation groupments of city populations of the mallard duck (Anas platyrhynchus). The cercariae of T. ocellata from rather distant geographical isolates (Moscow and Naroch Lake) differ by PCR pattern in greater extent than groupments of cercariae within Moscow. These distant isolates are considered to be members of separate populations. The cercariae of T. ocellata emitted from infected snails belonging to the different species (Lymnaea auricularia, L. ovata, L. pusilla pusilla) and during definite period (6 days with 24 h analysis) do not differ by the PCR patterns. T. ocellata cercariae emitted from L. auricularia in autumn period (from molluscs of the new generation in "new" summer infection) are found to be different significantly from the "spring" cercariae of the same year and the "autumn" ones of the previous year. The study of the experimentally reproduced life cycle of Opisthorchis felineus revealed an essential difference of cercariae genome. DNA from that in other development stages. This indicates, that genetic reorganisation in the genome of products of parthenogenetic development took place in the parthenita stage.