Phylogenetic relationships among Taphrina, Saitoella, and other higher fungi.

To determine the phylogenetic placement of the major groups of higher fungi, we sequenced the DNA sequences from the small-subunit ribosomal RNA (18S rRNA) coding regions from Taphrina wiesneri (synonym: T. cerasi) and Saitoella complicata and compared them to 18S rRNA sequences from the oomycetes, chytridiomycetes, zygomycetes, ascomycetes, and basidiomycetes. Here we demonstrate that the ascomycetes have at least two major evolutionary lineages. Taphrina wiesneri and Saitoella complicata form a monophyletic branch that diverged prior to the separation of other ascomycetes. The same treatment could be accorded to Schizosaccharomyces pombe.