I've seen this used as a plot seed for any number of space operas, but as far as I can recall, I haven't seen any that used it and also explained how they were able to somehow instill traits which, over hundreds of millions or billions of years, could not only remain present but unexpressed in the genomes of Nth-generation offspring, but could then, in response to some kind of extremely specific and complex stimulus, be expressed - but only when needed, and in perfect accord with the original intelligent design.
It sounds like I'm making fun here, and I'll admit I picked the phrase "intelligent design" with puckishness aforethought. But it's a serious question, and what I'm really looking for is media recs. Does anyone actually reckon with this, in a way that's plausibly compossible with our current understanding of genomic heredity?
(Introns and pseudogenes don't count, and yes, I remember that hilarious TNG S6 episode that used them as an excuse to give Barclay even more not-very-well-depicted psychological problems. Sure, these regions aren't translated into proteins, but they remain as susceptible to all the ordinary mechanisms of mutation as any other part of the genome. Not only that, being unexpressed, they are if anything less likely to be conserved than exons, so the "alien space magic hidden in non-coding DNA!" thing doesn't fly.)