New data on the distribution of chromosomal races in the supraspecies complex Cricetulus barabensis sensu lato (Rodentia, Cricetidae) and analysis of reproductive barriers among them

The taxonomy of striped hamsters from the supraspecies complex Cricetulus barabensis sensu lato (Rodentia, Cricetidae) is still controversial. The morphological and genetic differences between them are insufficient. In laboratory hybridization experiments, we obtained F₁ and F₂ hybrids from different combinations of mating between three chromosomal races. We found no evidence of reduced viability and fertility in the hybrids. In order to specify the distribution and detect natural hybridization, we analyzed the chromosomes of animals from potentially contacting populations of “barabensis” and “pseudogriseus” in southern Buryatia and central Mongolia. Two specimens with an abnormal karyotype were found in the “barabensis” population from the vicinity of Kharkhorin (central Mongolia), which can be considered as a result of distant hybridization. Karyological analysis of the hamster populations in southern Buryatia revealed parapatricity of the two chromosomal races, but regular hybridization between them was not found. In general, our data suggest that there is no intensive genetic interchange between the two chromosomal races.