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Yeast is the oldest domesticated microbe. Its potable fermentation products have sparked feuds, ended wars, instigated romance, and wrecked many a morning after. The organism's mark on science is no less notable. In the 1950s, mapping 26 genes was a challenge. Fifty years later, researchers have identified all 6,000, and they have extracted from this single-celled organism clues to the workings of all eukaryotic life. Scientists know more about cell cycle control from yeast than from any other organism.
Yeast primarily eat, divide, sporulate, and mate. These highly ordered and regulated functions appear in some form across all eukaryotic life, including mammals, and they look shockingly similar. "It's beyond similarity. I mean, it's almost identity," says yeast geneticist Leland Hartwell, whose genetic approach to the cell cycle won him the 2001 Nobel Prize.
The complex molecular cascades that control cell division across evolution were discovered with...