Submitted to: Mycological International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 17, 2002
Publication Date: N/A
Technical Abstract: As with most fungi, circumscription of yeast genera is based primarily on phenotype. Gene sequence comparisons, such as from 18S or 26S rDNAs, have shown that many presently defined yeast genera are not monophyletic, but single gene analyses seldom provide sufficient resolution to unambiguously circumscribe genera. Analysis of the ca. 80 known species of the Saccharomyces clade from EF-1, RNA polymerase II, cytochrome oxidase II and actin, as well as from 18S, 26S and mitochondrial small subunit rDNAs, individually gave congruent terminal lineages and, when analyzed in combination, provided strong genus-level support. Intergeneric relationships are less well resolved making family assignments uncertain. A comparison of species in the phylogenetically distant Stephanoascus/Blastobotrys clade gave similar results. Diagnostic phenotypes were recognized for many of the phylogenetically defined genera, but for some genera, there appeared to be no unifying morphological or physiological characters.