Fungal Populations and Species

John Burnet. Oxford University Press, New York. 2003. The fungi that most scientists are familiar with are tame and domesticated creatures indeed. My postdoctoral advisor, Bob Mortimer, was primarily responsible for the laboratory domestication of the baker's yeast Saccharomyces cerevisiae, which thanks to his efforts is now a favorite organism of geneticists around the world. This simple one-celled organism is far closer to us in evolutionary time than bacteria, but it has bacteria-like advantages in a laboratory setting. Like bacteria, it can be grown in separate colonies on a petri dish of defined medium, but it can also undergo meiosis and regular genetic recombination just like you or me. The first attempts by geneticists to utilize S. cerevisiae, in the 1930s, were disastrous—its genetics seemed inexplicable and its life cycle seemed quite deranged. Patiently Bob selected a laboratory strain that behaved itself. Its meiotic products all survived because they all had the proper number of chromosomes, and the haploid strains that resulted from meiosis could be maintained as haploids without suddenly reverting to diploids again as they did in most yeast strains.