This reminds me of those evolution experiments where they would take a bacteria that couldn't metabolize citric acid and put it in a citric acid environment and then freeze / sequence samples every few generations and see how long it would take for them to develop the mutations required to metabolize citric acid and they woudl find that the precursors to this ability was already latent in generations prior to the adaptation showing up.
https://en.wikipedia.org/wiki/E._coli_long-term_evolution_ex...