Saccharomyces paradoxus and Saccharomyces cerevisiae are associated with exudates of North American oaks

Genetic hybridization and karyotypic analyses revealed the biological speci es Saccharomyces paradoxus and Saccharomyces cerevisiae in exudates from No rth American oaks for the first time. In addition, two strains collected fr om elm flux and from Drosophila by Phaff in 1961 and 1952 were reidentified as S. paradoxus. Each strain studied showed a unique profile of chromosoma l hybridization with a probe for the retrotransposable element Ty1. The wil d distribution of natural Saccharomyces sensu stricto yeasts is discussed.