Send to

Choose Destination
See comment in PubMed Commons below
PLoS Genet. 2009 Jun;5(6):e1000517. doi: 10.1371/journal.pgen.1000517. Epub 2009 Jun 12.

Complex adaptations can drive the evolution of the capacitor [PSI], even with realistic rates of yeast sex.

Author information

  • 1Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.


The [PSI(+)] prion may enhance evolvability by revealing previously cryptic genetic variation, but it is unclear whether such evolvability properties could be favored by natural selection. Sex inhibits the evolution of other putative evolvability mechanisms, such as mutator alleles. This paper explores whether sex also prevents natural selection from favoring modifier alleles that facilitate [PSI(+)] formation. Sex may permit the spread of "cheater" alleles that acquire the benefits of [PSI(+)] through mating without incurring the cost of producing [PSI(+)] at times when it is not adaptive. Using recent quantitative estimates of the frequency of sex in Saccharomyces paradoxus, we calculate that natural selection for evolvability can drive the evolution of the [PSI(+)] system, so long as yeast populations occasionally require complex adaptations involving synergistic epistasis between two loci. If adaptations are always simple and require substitution at only a single locus, then the [PSI(+)] system is not favored by natural selection. Obligate sex might inhibit the evolution of [PSI(+)]-like systems in other species.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Public Library of Science Icon for PubMed Central
    Loading ...
    Support Center