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February 24, 2003

Genes interact WITH environment

Why does it always have to be one or the other?

I bring this up now because you will see it more and more often rearing its head in the strangest of places. At the Center for the Advancement of Health they are finding evidence, though it isn't interpreted as such in the article, for self-control to have a genetic basis. This is particularly interesting in light of the findings in recent years regarding polymorphisms in 5-HT2A, tryptophan hydroxylase, and others. Here's a nice summary of current research on serotonin and suicide. I have always felt that 5-HT2A signalling is related to emotional tolerance to events, and the idea connects the dots between the two phenomena nicely, if true. Of course, as mentioned in the NeLHM article, the statistics are far from conclusive.

Posted by grady at 09:52 PM

What I found most interesting was the notion that we can discover the things which deplete willpower, and those which replenish it.

Posted by: Grady at February 25, 2003 09:40 AM

That's very interesting... especially when I think back to the decades I spent skydiving, and remember that it was much easier to manage willpower during the week after I'd made a few jumps the previous weekend, than when I was feeling groundbound.

Serotonin levels? Something else? I know from wide experience that skydivers are very often told by their friends and significant others to go get their knees in the breeze, because they're getting testy...

Posted by: Troy at February 26, 2003 02:07 AM

'Nother thought on the "genes interact WITH environment" meme: CopyCat, the cloned kitten, resembles her genetic mother, but is not even close to identical in appearance. Speculation is that inactivation of X-chromosome genes and the different prenatal environment are the reasons... in particular, X-inactivation turned off the orange in CC's coat, and environment seems to have made CC's build quite a bit different than her mom's.

If only all discoveries could be so controversy-inhibiting!

Posted by: Troy at February 26, 2003 02:35 AM

Genetic basis for self-control or lack thereof ....


Why do I think of negro crime rates when I read that?

Naughty, naughty me !!!

Posted by: John Ray at February 26, 2003 06:42 AM

X inactivation is a really big thing. It's means that there's basically a 50-50 chance(except for some things for which the maternal origin is preferred - I don't know of anything that has a paternal preference - anyone?) that you'll express the maternal or paternal X-linked genes. There is a controversy right now around the effects of environment on X-inactivation. For the other 22, there are also environmental epigenetic effects regulating gene expression, so even when the genetic material is the same, the rate at which the gene is transcribed or the position effect of the cis-acting sequences is going to be different because that information is not inherited. In fact, important developmental processes depend on mRNA that was present in the egg or sperm or on maternal protein expression. So clearly there are many environmental effects to be considered, starting with fertilization, up to the point of expression of the trait. Far from inhibiting controversy, I think it opens up another whole area for contention.

Posted by: Grady at February 27, 2003 02:51 PM

john jay - it's not wrong to think something like that, but it is important to realize that there could be many explanations for the phenomenon, and to pick the most insulting theory right off the bat isn't something I would be letting other people know I do.

Let me illustrate with a story -
I was driving around last month, and I kept track of the number of people who did "stupid traffic tricks", basically reckless driving and not paying attention. 19 out of 20 were little black girls, and as many on cell phones as not.

I just made the story up, but here's the point:

Does that mean that young black girls are bad drivers? Would it still mean they are bad drivers if I was in a section of town where 19/20 drivers overall were black?

More to the point, since crime doesn't always have to do with self-control, what about obesity(for which I can also present evidence of genetic influence)? How would the fact that african americans have a defective allele for a cholesterol transport protein change the picture here?

I don't mean to sound like I'm attacking you, but the fact is that we get accused enough of being racist here, so if you're going to make a comment like that you need to present a reasoned argument, backed up by evidence. There's room enough for wild-eyed speculation on your own blog.

Posted by: Grady at February 27, 2003 03:16 PM

Grady, good points about the many and varied influences on gene expression. The particular controversy I had in mind was the "grow an identical clone" meme which leads to armies of clones, brain transplants (or downloads of brain "recordings") into one's clone as a life-extension/resurrection technology, and the rest of the sfnal/horrorfilm fantasies.

But you're right -- it will be a long time before the recursive procedure converges to true knowledge...

Posted by: Troy at March 2, 2003 10:06 PM