Another case of evolutionary "pre-adaptation"

Rapid evolution of novel forms: Environmental
change triggers inborn capacity for adaptation

Let's see. A protein normally inhibits expression of genotypic "mutations" (that is, their expression into variant phenotypic traits). But under stress, production of the protein itself becomes suppressed and, as a result, more of the genotypic "mutations" become phenotypically expressed. And those "mutations", which have been riding along silently in the genome of this fish, having originated we know not how, just happen to include variants (when phenotypically expressed) that are adaptive in the environment that produces the stress.

It's just too pat. Carrying around a reservoir of unexpressed mutations? Just for fun? Just "in case"? Just "by chance"? I don't think so.

See report at   http://wi.mit.edu/news/archive/2013/rapid-evolution-novel-forms-environmental-change-triggers-inborn-capacity