Mutants

"That’s right. Armand Leroi is a biologist at Imperial College, London. And this is a really wonderful book because Leroi takes what could have just been a freak show and turns it into a really amazing experience. He writes about these people as people. He finds wonderful portraits of individuals – for example, some of them are covered in hair and look like wolves – and he tells the story of their lives in quite beautiful prose. He also uses their conditions to talk about the rules of development. What is important is that mutants are not random. You don’t get a random range of deformities; they have certain patterns. So you don’t see people developing an eye on their hands, for example. That just doesn’t happen. But it is possible for two eyes to become one. So, why is it that you don’t see eyes developing on hands but you do see two eyes becoming one? And why do Siamese twins form in particular patterns and not others? You don’t see twins joined at the toe. The reason is that our development follows a pretty tight path. When the genes that are governing our development are mutated, they don’t get disrupted in all that many different ways. These regularities in disruptions can reveal to you what is going on underneath. This is a tried-and-true method in biology. When people are trying to understand how the brain works, one of the most important things they can do is to study people who have different kinds of psychological disorders. People can lose their ability to use language but not their ability to perceive music, and that starts to show that, actually, there are networks for these different kinds of cognition. The same thing goes with development. Three biologists won the Nobel Prize in 1995 for studying how fruit flies sometimes develop extra wings or sprout legs on their heads. Those kinds of deformities let them zero in on genes that define a body from head to tail. They studied it in fruit flies – and then, lo and behold, it turns out that we actually have the same genes. They govern our anatomy. When those genes mutate in us, we can end up with extra fingers. And so again there is a hidden unity under there. Yes. And he does such a beautiful job of showing that and doing it with poetry. He is able to show the beauty in a birth deformity."