It is a rote of modern molecular biology classrooms to stress the importance of DNA–
protein interactions by pointing out that species such as the bonobo and the human being
share more than 95% of their genes – a level of similitude far exceeding that of, say, the
translations of the Odyssey by Robert Fitzgerald and by Samuel Butler. The nonnegligible
differences between our hirsute cousins and us, the argument goes, must find its explana￾tion not so much in what genes we both use but in when and to what extent they are used.
Hence the truly vital importance of understanding how regulatory proteins, be they active
or passive, activating or inhibiting, interact with the genetic material to see it expressed in
the proper way