Phenylketonuria (PKU) requires both inherited broken gene copies and dietary intake of phenylalanine to manifest.

“a classic one from genetics has to do with a genetic disease called phenol ketonuria or PKU uh which is uh an inability to uh to metabolize uh the dietary amino acid phenyalanine and uh so uh in order to have this you have to inherit broken copies of this Gene from both your mother and your father so it's a so-called recessive trait and here's where the experience comes in it only matters if you eat foods rich and fenal alanine if you don't it doesn't matter that you inherited these things right so that's a way which genes and experience interact”