THE PHYLOGENETIC-RELATIONSHIPS OF THE Q6-EQUIPPED GENERA TORULASPORA LINDNER AND ZYGOSACCHAROMYCES BARKER (SACCHAROMYCETACEAE) BASED ON THE PARTIAL SEQUENCES OF 18S-RIBOSOMAL AND 26S-RIBOSOMAL RIBONUCLEIC-ACIDS

Eleven strains of Torulaspora and Zygosaccharomyces species were examined for the partial base sequences of 18S and 26S rRNAs. In the partial base sequences in positions 493-622 (130 bases) of 26S rRNA, there were 88-91% and 70-92% maximum homologies within the genera Torulaspora and Zygosaccharomyces, respectively. The maximum homologies were 70-90% between the two genera. The species of the two genera had 73-88% maximum homologies with Saccharomyces cerevisiae. In the partial base sequences in positions 1611-1835 (225 bases) of 26S rRNA, there were 3-0 and 16-1 base differences within the two genera, respectively. The base differences were 15-0 between the two genera. The two genera had 17-8 base differences with S. cerevisiae. In the partial base sequences in positions 1451-1618 (168 bases) of 18S rRNA, there were 0 and 3-0 base differences within the two genera, respectively. The base differences were 2-0 between the two genera. The two genera had 3-1 base differences with S. cerevisiae. Zygosaccharomyces cidri and Z. fermentati occupied a unique situation (base differences, 3-2). The data obtained were discussed with regard to the phylogenetic relationships and the taxonomic positions of Torulaspora, Zygosaccharomyces, and Saccharomyces.