TO BUD UNTIL DEATH - THE GENETICS OF AGING IN THE YEAST, SACCHAROMYCES

Individual cells of the budding yeast, Saccharomyces cerevisiae, have a limited division capacity and undergo characteristic changes as they senesce, primarily increasing both their cell size and cell cycle tim e. The mortality curve for ageing yeast cells can be described by the Gompertz equation, the classical definition for an ageing population. Recent work from several laboratories has demonstrated that genes can determine the yeast lifespan. Studies with the UTH genes have implicat ed changes in transcriptional silencing during yeast ageing, but the r oles of the RAS2, LAG1 and PHB1 genes in regulating yeast longevity ar e still unclear. What is becoming clearer, however, is that yeast agei ng is more than just a bud scar phenomenon.