Living systems are simply not as they would be if all their components parts had been intentionally orchestrated. So when we talk of someone who "plays" the genome, we must recognise that no one set of molecules is given a position of privilege over another. Nature always use whatever comes to hand. That is also how it has evolved the pattern of regulation that we can to some extent imagine as the "organist". The components of a system may survive only because that higher-order system conforms to a particular, successful logic of survival of the organism, but that does not mean each component operates in an ideal way, or the best way in conformity with that logic. Indeed the system has to accommodate all sorts of lower-level quirks to be viable at all. Enrico Coen put it well. "Organisms", he said, "are not simply manufactured according to a set of instructions. There's no easy way to separate instructions from the process of carrying them out, to distinguish plan from execution".
From "The music of life - biology beyond genes" by Denis Noble