The evolution of the evolvability properties of the yeast prion [PSI+]

Joanna Masel, Aviv Bergman

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Saccharomyces cerevisiae's ability to form the prion [PSI+] may increase the rate of evolvability, defined as the rate of appearance of heritable and potentially adaptive phenotypic variants. The increase in evolvability occurs when the appearance of the prion causes read-through translation and reveals hidden variation in untranslated regions. Eventually the portion of the phenotypic variation that is adaptive loses its dependence on the revealing mechanism. The mechanism is reversible, so the restoration of normal translation termination conceals the revealed deleterious variation, leaving the yeast without a permanent handicap. Given that the ability to form [PSI+] is known to be fixed and conserved in yeast, we construct a mathematical model to calculate whether this ability is more likely to have become fixed due to chance alone or due to its evolvability characteristics. We find that evolvability is a more likely explanation, as long as environmental change makes partial read-through of stop codons adaptive at a frequency of at least once every million years.

Original languageEnglish (US)
Pages (from-to)1498-1512
Number of pages15
Issue number7
StatePublished - Jul 1 2003
Externally publishedYes


  • Adaptation
  • Canalization
  • Epigenetic inheritance
  • Genetic assimilation
  • Population genetics
  • eRF3
  • sup35

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Agricultural and Biological Sciences(all)


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