evolvability

Carey CC, Gorman KF & Rutherford S 2006 Modularity and intrinsic evolvability of Hsp90-buffered change. PLoS ONE 1:e76.

• the relevance of Hsp90-buffered variation for evolution has been most often challenged by the idea that large morphological changes controlled by Hsp90 are unconditionally deleterious
• within the limitations of laboratory tests of fitness, this large morphological change controlled by Hsp90 was selectable independent of strong, correlated and unconditionally deleterious effects
• abundant, polygenic variation hidden by Hsp90 allows potentially deleterious alleles to be readily replaced during selection by less deleterious alleles with similar phenotypic effects
• the complex genetic architecture of Hsp90-buffered variation supports a remarkable modularity of Hsp90 effects on quantitative and qualitative phenotypes
• consistent with the 'Hsp90 capacitor hypothesis' and standard quantitative genetic models of threshold traits