The species of budding yeast used by brewers and bakers. Strains of brewer's and baker's yeast have special properties. Baker's yeast can raise bread five times faster than brewer's yeast, but baker's yeast gives beer an undesirable yeasty flavor and settles out poorly. When nutrients are plentiful, wild type strains of S. cerevisiae proliferate as diploid cells. If starved, they go through meiosis to form haploid spores. These can later germinate and proliferate as haploid cells, or they can fuse to reform diploids. The demonstration that yeast DNA has a high content of AT relative to GC disproved the tetranucleotide hypothesis (q.v.). S. cerevisiae was the first eukaryote to have its entire genome sequenced. It contains 12,068,000 base pairs, divided among 17 chromosomes. Its 5,885 ORFs make up about 70% of the genome. Only about 4% of the genes contain introns (q.v.). This is unusual, since 40% of the genes of Schizosaccharomyces pombe (q.v.) contain introns. In S. cerevisae there are 140 rRNA genes in a large tandem array on chromosome 12. The 40 genes for snRNAs and the 275 genes for tRNAs are dispersed among all the chromosomes. S. cerevisiae is a favorite species for studying the genetic regulation of progression through the cell cycle. See Classification, Fungi, Ascomycota; Chronology, 1949, Ephrussi et al.; 1965, Holley et al.; 1970, Khorana et al.; 1973, Hartwell et al.; 1974, Dujon et al.; 1979, Cameron et al.; 1980, Clark and Carbon; 1985, Boeke et al.; 1989, Kaback, Steensma, and DeJonge; 1992, Oliver et al.; 1996, Goffeau et al.; 1999, Galitsky et al.; 2000, Rubin et al.; bud, cassettes, centromere, Chargaff rule, genetic code, mitochondrial DNA, omnipotent suppressors, orphan, petites, Plasmodium, Ty elements, universal code theory, yeast artificial chromosomes (YACs), yeast two-hybrid system.
Subjects: Genetics and Genomics.