Submitted to: Yeasts International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: August 25, 2001
Publication Date: N/A
Technical Abstract: Gene sequence analyses have placed yeast systematics within a phylogenetic framework that provides an understanding of natural species relationships and allows rapid, accurate species identification as well as predictions of unique metabolic properties. Molecular comparisons have demonstrated that the budding ascomycetous yeasts make up a single group or clade among the fungi that is a sister group to the euascomycetes. Basal to these two clades is a phylogenetically divergent group that includes Schizosaccharo- myces, Protomyces, Taphrina, Saitoella, Pneumocystis and Neolecta. In contrast, the basidiomycetous yeasts occur in several phylogenetically distinct groups. Gene sequences, such as domain D1/D2 of large subunit rDNA, the ITS region and actin, are usually sufficiently variable to allow resolution of individual species. A number of practical applications have arisen from molecular comparisons. Species may be rapidly identified by sequencing or by use of oligonucleotide "molecular probes" based on these sequences. Species-specific probes with fluorescent labels are presently being produced commercially, and aggregates of species-specific probes should soon be available as arrays on chips. Biotechnological exploita- tion of yeasts can be facilitated through knowledge of species relation- ships. While many physiological reactions, such as glucose fermentation, are characteristic of broad groups of yeasts, certain other reactions, such as assimilation of methanol or uric acid are restricted to particular groups. Knowing the phylogenetic placement of a species allows predictions of the compounds that might be metabolized. Further, the unique gene sequences of the group of interest can be used for rapid screening of additional natural isolates with the required metabolic function.