06 February 2010

Signature in the Cell: Chapter 3

The chapter is called "The Double Helix," and there's not much to say about it. Meyer provides a fairly standard narrative of the discoveries that led to Watson and Crick and molecular biology. Anyone who's read The Eighth Day of Creation, along with a decent genetics textbook and/or a memoir by one of the principals (What Mad Pursuit by Francis Crick is a personal favorite) will already know everything here. Two observations.

1. Meyer makes a basic error on page 66 while describing the early evidence that DNA is the genetic material. He's describing the classic experiments of Avery, MacLeod and McCarty on Pneumococcus bacteria that can be transformed from one strain into another. The phenomenon of transformation had been discovered by Frederick Griffith in the 1920's.

If a deadly strain of the bacteria was first heated to death, the strain was harmless when injected into mice. No surprise there. The mice were also unharmed when injected with a living but nonvirulent strain of the virus.
Do you see the mistake? Now, if you're not a biologist, you might think the error is trivial, purely semantic, a typing glitch induced by the proximity of the word 'virulent.' And that last part is probably right. But this biologist finds the error more significant, and I suspect others would agree. The difference, I think, is that I can't imagine mistaking a virus for a bacterium; it's like mistaking a pencil for a sequoia.

A person who would make that mistake – and leave it in his awesome, groundbreaking treatise on 21st-century biological science – is a person who doesn't think very much about viruses or bacteria. A person who would make that mistake is a non-specialist. A layperson. And of course, Stephen Meyer is a layperson. He's clearly not a biologist, or even a person who's particularly knowledgeable about biology. (That paper in the Proceedings of the Biological Society of Washington became infamous due to political disputes; I thought it was most notable for being lame.) This is obvious from my reading of this book and his other work, and the mistake on page 66 just serves to remind me that despite the thunderous praise from fans on the dustjacket and in the ID-osphere, Meyer just isn't all that impressive as a scientific thinker. Call me a jerk, but I expect a hell of a lot more from someone who wants to rewrite science (and its history).

2. Alas, I cut off Meyer's description of Griffith's famous experiment. (You can read a great overview of the work of Griffith and Avery et al. at Nature's cool Scitable site.) What Griffith showed was that the nonvirulent (i.e., nonlethal) strain of bacteria could kill mice if it was injected along with heat-killed virulent bacteria. The nonvirulent bacteria had been transformed into virulent bacteria by being in the presence of dead virulent bacteria. (To this day, the process of introducing DNA into bacteria is called transformation.) Fifteen years later, Avery and colleagues were trying to figure out the nature of the transforming substance. Here's how Meyer sets the stage:
There were two possibilities. Either the dead strain was coming back to life–but this was absurd–or something in the dead strain of bacteria was being transferred to the living strain, making it suddenly lethal. –pages 67-68
Now I think this is very interesting. Without any further comment and no apparent justification, Meyer dismisses a major hypothesis, even labeling it "absurd." The idea of bacteria "coming back to life" is far-fetched, I'll grant you, but I guess I'm wondering whether the irony of Meyer's casual vacation of the reanimation hypothesis is something that only Shakespeare lovers can detect. Avery, MacLeod and McCarty didn't consider reanimation, as near as I can tell, but that could just be their obvious naturalistic bias, don't you think? Avery and colleagues did, on the other hand, deal with the possibility that the nonlethal bacteria spontaneously mutated into a lethal strain. Their stubborn naturalism comes through rather clearly in their writing, I must say. Someday I'd love to see an explanation for why Steve Meyer considers the reanimation hypothesis to be absurd. And I'm curious to know whether he would understand why this is important.

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