Bullet points from human genetics for you to shoot off.

Arena

Armand Marie Leroi likes mutants, because they serve a purpose, and it's not just keeping Bravo TV on air. In altering the meaning of individual genes, mutations suggest what those genes meant to the body in the first place. In other words, a man with a toe growing from his tongue helps us to understand what causes tongues to grow correctly. What's remarkable in humans is not the things that can go wrong (though he illustrates these - Cyclopses, extra titties, piebald skin - in gruesome detail) but that most of us turn out alright.

Arena (May 2004)