Just putting this out there; but if it were in the story that these powers could be dampened by a certain field, like a strong electrical field like in a 1920s police tazer, then maybe the poweres themselves arise from our bodies use of a certain field that we tap into. And different DNA results in different adaptations from the field. Such as super speed in one case resulting from fast twitch muscle tapping into the field, and super intellegence resulting from either gray or white matter that can tap into the field. We could even say that theres a special organelle inside the cells of supers, such as an adapted mitochondria... we'd still need to think of a name for it. How about Asclepichondria after the son of Appolo and god of medicine Asclepius.