Evolutionary capacitance

Evolutionary capacitance is a biological theory stating that living systems have the ability to accumulate genetic variation that has no phenotypic effect until the system is disturbed (perhaps by stress), at which point the variation has a phenotypic effect and is subject to natural selection. This mechanism would allow for rapid phenotypic change in a population, and rapid adaptation to new environmental conditions.

There is currently no consensus about whether capacitance has a meaningful effect on natural systems, let alone whether there might be selection for evolutionary capacitance. There is also debate over whether capacitance is a trait of particular genes, or whether it is a general aspect of genetic networks, or of any presumptive mechanism of switching between states.

The possibility of genetic capacitance has been attributed to prions and heat shock proteins.