Hsp90 depletion goes wild

Abstract

Hsp90 reveals phenotypic variation in the laboratory, but is Hsp90 depletion important in the wild? Recent work from Chen and Wagner in BMC Evolutionary Biology has discovered a naturally occurring Drosophila allele that downregulates Hsp90, creating sensitivity to cryptic genetic variation. Laboratory studies suggest that the exact magnitude of Hsp90 downregulation is important. Extreme Hsp90 depletion might reactivate transposable elements and/or induce aneuploidy, in addition to revealing cryptic genetic variation. See research article http://wwww.biomedcentral.com/1471-2148/12/25.

Figure 1

The extent of Hsp90 depletion affects the mechanism by which phenotypic effects are induced. To work as an evolutionary capacitor, facilitating evolvability above and beyond the effects of mutagenesis, induced variation must persist for multiple generations, but also be reversible once genetic assimilation is complete. None of the three proposed effects of Hsp90 depletion clearly meets both hurdles.