Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/1998
Publication Date: N/A
Citation: N/A Interpretive Summary: Changes in the molecular sequence of the genetic material termed ribosomal DNA were used to estimate genetic relationships among the 500 known species of ascomycetous yeasts. Among these yeasts are Saccharomyces cerevisiae that is used to make bread, Eremothecium ashbyi used for production of the essential vitamin riboflavin (B2), and the human pathogen Candida albicans. It was found that there were sufficient changes in the molecular sequence to allow identification of individual species, thus providing for the first time a reliable method for this task that will utilize recent advances in biotechnologically important molecular sequencing technologies. The study also demonstrated that many genera are incorrectly defined. In addition to rapid identification, the data can be used to predict the metabolic properties of yeasts and this will allow their increased exploitation in agriculture and industry.
Technical Abstract: The phylogeny of approximately 500 species of ascomycetous yeasts was analyzed from divergence in the variable region D1/D2 of large subunit (26S) ribosomal DNA. The divergence in this region is generally sufficient to resolve individual species, resulting in the prediction that 57 currently accepted species are synonyms of previously described taxa. The region provided insufficient phylogenetic resolution to confidently circumscribe most genera, but the analyses demonstrate that most genera are not phylogenetically defined. Evidence is presented that the ascomycetous yeasts underwent a significant species radiation following the late Permian global extinction event.