Patterns of gene expression are to organisms as melodies and harmonies are to sonatas. It's all about which sets of proteins appear in a cell at the same time (the chords) and which sets come before or after other sets (the themes) and at what rate they appear (the tempos) and how they modulate one another (the developments and transitions). When these patterns go awry we may see malignancy. When they change by mutation we can get new kinds of organisms. When they work, we get a creature.

p. 59 - The Sacred Depths of Nature (1998)