evolvability

McGuigan K & Sgro CM 2009 Evolutionary consequences of cryptic genetic variation. TREE 24:305-311.

• little empirical evidence that stressful or novel environments release cryptic genetic variation, or that, once released, it contributes to phenotypic evolution
• recent studies of Hsp90 have demonstrated release of cryptic genetic variation for discrete, but not necessarily for continuous, traits
• manipulation of Hsp90 in Arabidopsis and in Danio suggests cryptic genetic variation for continuous traits, but the effect was highly dependent on genetic background

• there is little difference between evolutionary scenarios based on visible versus cryptic genetic variation