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Jun 17 2005

Reading diary, 6/17/05: Mutants: On Genetic Variety and the Human Form

Neat. Tough sledding, but neat.

“Mutants” Armand Marie Leroy is about, well, mutants: people born with genetic or other birth defects. Unlike most books I’ve seen on these people, this isn’t a social history of freak shows and freak society. It’s a science-for-the-layperson book, looking at how humans (and other animals) develop in the womb, and taking what happens when that process goes wrong as a way of understanding what happens when it goes right.

The book is tough going at times. It really, really doesn’t dumb down the science; as a result, there were good-sized stretches that I didn’t follow at all and just had to skim. And I’m usually pretty good with this “science for laypeople” kind of thing.

But I found it very much worth it. I have a far better sense now (which is to say, any sense at all) of how exactly DNA and embryonic development works, how the genetic code tells an embryo to do what it does. And I have a much, much better sense of gaping awe and wonder at the fact that this un-fucking-believably complicated and delicate process even works at all, not to mention that it works most of the time. I’m feeling much more humble since reading it: less inclined to gripe about my petty aches and pains (asthma, allergies, bum knees, etc.), and more grateful for the fact that my body basically works, and has for over 40 years.

Nitpick: I do wish there had been more pictures. Not just because the pictures it does have are cool, but because I think I would have been baffled less often if there had been more visual imagery.

Books I’m currently still in the middle of:

“Guns, Germs and Steel” by Jared Diamond
“The Forbidden Zone” by Michael Lesy
“Will The Circle Be Unbroken?” by Studs Terkel
“Meditations” by Marcus Aurelius
“The Onion Ad Nauseum: Complete Archives Volume 14″ by the staff of The Onion
“Zounds! A Browser’s Dictionary of Interjections” by Mark Dunn
“Existentialism and Human Emotions” by Jean-Paul Sartre
“Essays” by Michel de Montaigne

1 comment

  1. 1
    Kris

    Ok, here’s my take on the book, Mutants. The pictures are cool, in that weird, creepy sort of way. The author was very good at providing back story and entertaining historical examples of mutants, but the science left me either wanting or irritated. It desperately wanted at least one diagram showing how the different tissues in animals arise from a blastula. The book mixes different means of arriving at the mutated state, such as environmental effects vs. inherited effects, but isn’t really very clear in explaining the really cool and wonderous aspects of developmental biology. I found Matt Ridley’s “Nature via Nurture” much more interesting in terms understanding the interconnected relationship between environment and genes in shaping who we are. And I’m currently reading “Endless Forms Most Beautiful”, by Sean Carroll, which has a much more lucid explanation of exactly how all those homeotic genes work. Besides, he’s got really cool pictures of fruit fly embryos all lit up with patterns of gene expression, a much more evolutionary bent to his focus, and he’s really excited about this stuff. I think the most interesting thing about the recent exploration of how these genes control development is the realization that pretty much all animals are using the same genes to build their bodies.
    And then Sean Carroll goes a step further and points out, it’s not enough to know that our genetic make-up and a chimp’s is 98% the same, we want to know how we’re different as well. Obviously there’s some differences in development, and those are hard to untangle without subjecting a bunch of human embryos to unspeakable horrors. But he talks about a couple of genes we do know about, one of which is a protein that is expressed (made in the cells) in the jaw muscles of our nearest relatives, the apes, but not in us. We have the gene for the protein, but it’s missing a section, and so no longer makes an active protein. Ho Hum. So What? Well, one of the things that makes us human is our large and bulbous skull (which might explain why our images of aliens often have enormous bulging heads) and wimpy jaw muscles. The two things are related; big jaw muscles need thick skull bones and perhaps a large skull ridge to which they can attach. So lacking a functional protein in our jaw mucles makes it possible to be brainy compared to other apes.

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