I like to think of genes as keys on a piano. But the genome also includes the a lot of the musical score. You can get a lot of different songs with a finite s

I like to think of genes as keys on a piano. But the genome also includes the a lot of the musical score. You can get a lot of different songs with a finite set of keys played in different combinations and sequences and amplitudes. In this picture, most of evolution wouldn't be changing the keys but changing the score.