Genetic structure, morphological variation, and gametogenic peculiarities in water frogs ( <i>Pelophylax</i> ) from northeastern European Russia

The edible frog, Pelophylax esculentus, is a hybrid form that reproduces via clonal propagation of only one the parental genomes through generations hybrids while genome other species eliminated during gametogenesis. Such reproductive ability requires to coexist with or rarely both causing formation so-called population systems. Population systems and biology water frogs from east range remained partially unexplored. In this study, we investigated distributions, systems, genetic structure, types gametes, morphological variability genus northeastern parts their ranges (Mari El Republic adjacent territories, Russia). We examined 1,337 individuals 68 localities using traits combined DNA flow cytometry multilocus approach (fragments nuclear two mitochondrial genes). revealed five systems: “pure” populations P. ridibundus (R) lessonae (L), mixed (R-L) along (R-E-L), as well esculentus (L-E). However, (E) (R-E) were not found. All studied by diploid. Analysis gametogenesis showed majority males, females L-E system, produced gametes genome. in R-E-L usually sterile. reproduction such primarily based on crosses males females. Molecular analysis presence introgression Anatolian marsh frog (P. cf. bedriagae) into esculentus. observations alleles haplotypes bedriagae same suggest de novo local hybrids. Balkan kurtmuelleri) supports hypothesis regarding migration old hemiclonal lineages glacial refugia. Finally, diagnostic value various characteristics was discussed.