Historical Evolution of Laboratory Strains of Saccharomyces cerevisiae

Budding yeast strains used in the laboratory have had a checkered past. Historically, the choice of strain for any particular experiment depended on the suitability of the strain for the topic of study (e.g., cell cycle vs. meiosis). Many laboratory strains had poor fermentation properties and were not representative of the robust strains used for domestic purposes. Most strains were related to each other, but investigators usually had only vague notions about the extent of their relationships. Isogenicity was difficult to confirm before the advent of molecular genetic techniques. However, their ease of growth and manipulation in laboratory conditions made them "the model" model organism, and they still provided a great deal of fundamental knowledge. Indeed, more than one Nobel Prize has been won using them. Most of these strains continue to be powerful tools, and isogenic derivatives of many of them-including entire collections of deletions, overexpression constructs, and tagged gene products-are now available. Furthermore, many of these strains are now sequenced, providing intimate knowledge of their relationships. Recent collections, new isolates, and the creation of genetically tractable derivatives have expanded the available strains for experiments. But even still, these laboratory strains represent a small fraction of the diversity of yeast. The continued development of new laboratory strains will broaden the potential questions that can be posed. We are now poised to take advantage of this diversity, rather than viewing it as a detriment to controlled experiments.