GENETIC-CHARACTERIZATION OF PATHOGENIC SACCHAROMYCES-CEREVISIAE ISOLATES

Saccharomyces cerevisiae isolates from human patients have been geneti cally analyzed. Some of the characteristics of these isolates are very different from laboratory and industrial strains of S. cerevisiae and , for this reason, stringent genetic tests have been used to confirm t heir identity as S. cerevisiae. Most of these clinical isolates are ab le to grow at 42 degrees, a temperature that completely inhibits the g rowth of most other S. cerevisiae strains. This property can be consid ered a virulence trait and may help explain the presence of these isol ates in human hosts. The ability to grow at 42 degrees is shown to be polygenic with primarily additive effects between loci. S. cerevisiae will be a useful model for the evolution and genetic analysis of funga l virulence and the study of polygenic traits.