Well.... proteins play an important role in how DNA is expressed. And you get your initial set of proteins, like your DNA, from your parents (mom mostly), so th

Well.... proteins play an important role in how DNA is expressed. And you get your initial set of proteins, like your DNA, from your parents (mom mostly), so they set the starting conditions. Then during your life what you do has a methylation effect on your DNA. Thus the total information that makes up a human is actually quite a bit bigger then the information contained in his or her DNA.