Speciation and hybridization

The Department studies speciation, as patterns of «nonorthodox» or accidental speciation, related to clonal reproduction, hybridization, and polyploidy, as well as cryptic speciation in temporate and tropical amphibians and reptiles using allozyme analysis, cytogenetic and molecular methods.

The most notable example of such a study is the long-term work on unisexual rock lizards of the Caucasus. The methods utilized include techniques such as chromosome study, protein electrophoresis, and analysis of nuclear DNA. These techniques increase understanding in the following areas: the role of hybridization in the origin of parthenogenetic forms of lizards, the relations between these lizards and bisexual species, the role of interspecific hybridization in the appearance of triploid males, the influence of occasional males in parthenoforms, the level of genetic divergence between forms, and the degree of genetic heterogeneity in unisexual forms.

Hybridogenic complexes of European green frogs, the diploid-tetraploid complex in green toads of Central Asia, and other interesting cases of uncommon speciation have been studied by Leo Borkin and his coauthors. Geographic (allopatric) speciation has also been studied. Levels of genetic heterozygosity and divergence (in biochemical loci) were estimated in continental and insular populations and in subspecies and closely related species of some groups of amphibians and reptiles.

Comparative karyological study of lizards by Larissa Kupriyanova allowed the formulation of new ideas concerning chromosome evolution in these forms and some theoretical proposals about karyological evolution in general.