[Taxonomic genetics of Zygowilliopsis yeasts].

Genetic hybridization analysis was conducted with 16 natural Zygowilliopsis strains isolated in different geographical regions and maintained in collections under species names Z. californica, Hansenula dimennae, and Pichia populi. Genetic relatedness was determined on the basis of mating, viability of hybrid progeny, and meiotic recombination of markers. Four new biological species are recognized in the former monotypic genus Zygowilliopsis. Species Z. californica and Zygowilliopsis sp. 3 probably include divergent geographical populations. It is necessary to reconsider the species composition of the genus Zygowilliopsis and generic assignment of P. populi yeasts. Genetic and molecular identifications of the Zygowilliopsis species are in perfect agreement.