Saturday, September 22, 2007


From the Archives

(March 2005) Maybe I should call this entry “Farewell Evolution?, or, Mendel, We Hardly Knew Thee” or something instead ... and I sure wish I remembered more from my genetics and biology coursework because this discovery of a little mustard plant that “fixed” its flawed gene is utterly fascinating—as is the fact that the genome isn’t even made of DNA.

So the little self-improvement plant that could—let’s call our plant representative Mildred just for fun, shall we? Yes, Mildred the Mustard Plant, that’s catchy—so this little Mildred inherited a defective gene from mom and pop yet somehow reverted to normal, improved on heredity.

Now yes, smartypants, it's true that scientists have altered genes for a while now, but they need a template, a corrected copy of the gene for mutation purposes. Mildred’s actual gene changed. No template. No fog and mirrors.

How’d she correct the actual sequence of DNA units in her own gene? Did Mildred just reach down into her magical kangaroo pouch or something and pull out a backup copy of the flawless sequence ’cause she wanted to be normal, Mom, just like the other little mustard seeds?

Could this ability to correct inherited defects apply across the board in nature or is it limited to Mildred and her brothers and sisters? And what has Mildred done to Mendel’s laws of inheritance? For that matter, what does this handy back-up system that allows organisms to fix themselves—or, as NYT science writer Nicholas Wade so elegantly puts it, to generate novelty—what does this back-up system do to the theory of evolution, to the assumption that mutations, not back-up systems, fix us?

Wade made this observation, too:
The finding could undercut a leading theory of why sex is necessary. Some biologists say sex is needed to discard the mutations, almost all of them bad, that steadily accumulate on the genome. People inherit half of their genes from each parent, which allows the half left on the cutting room floor to carry away many bad mutations. Dr. Pruitt said the backup genome could be particularly useful for self-fertilizing plants, as arabidopsis is, since it could help avoid the adverse effects of inbreeding. It might also operate in the curious organisms known as bdelloid rotifers that are renowned for not having had sex for millions of years, an abstinence that would be expected to seriously threaten their Darwinian fitness.

If humans contain backup copies of correct genes then I want to go back to whatever great-great whatever did not have schizophrenia and diabetes and bypass “the usual mechanisms of heredity.” My family's odds of passing schizophrenia on are incredibly high too, and I would like to correct that in all immediate my family members.

(And let’s don’t even talk about how much I won’t let myself ponder which of my numerous nieces and nephews will start showing the signs, the shift into paranoia...)

FINAL FACTOID: the mutated gene is known as a hothead gene .. and I just know there’s a Hothead Paison joke in there somewhere. (O hey, I got it and can see the headline now: Liberal scientists hatch evil plan to turn GOPers into lesbian hotheads!)

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