DNA BASE COMPOSITION OF SOME SPECIES OF YEASTS AND YEAST-LIKE FUNGI

Abstract

DNA base composition (GC content) of 44 strains of yeasts and yeastlike fungi which represent 36 species belonging to 19 genera was calculated from the thermal denaturation temperature (Tm) of DNA.
The GC content of these fungi ranged from 31.5 to 62.7%. Three species of Rhodosporidium showed GC values of 50.5%, 64.9-65.4%, and 67.1-67.3%, respectively, and were considered to be well-defined species. Seven species of Tremella showed a GC content of 47.6-58.5% which fell within the range of that reported in Cryptococcus. Three species of Protomyces and one species of Taphrina showed a GC content (52.0-52.4%) similar to one another, and the close relation assumed between these genera was supported. Endomycopsis javanensis and E. capsularis showed GC values of 31.5% and 43.4%, respectively, which were low and high extremes of this genus. Three species of Trichosporon showed the GC content in the range of 45.6 to 62.7%. Trichosporon lodderi, which is now regarded as a synonym for Candida tropicalis, showed a GC content of 45.6% which was about 10% higher than that of C. tropicalis. This species is considered to be different from C. tropicalis. Sterigmatomyces elviae showed a GC content of 51.5% and demonstrated strong urease activity, and is assumed to be related to heterobasidiomycetes.