June 24, 2003
Saw a fairly old page the other day called "Things Creationists Hate." Basically, it's a bunch of evidence that humanity did, in fact, evolve from earlier forms of life, and that the dirtball we call home really is more than 6000 years old.
One of the indirect proofs mentioned in favor of evolution (which I'll admit wouldn't mean much if it was the only evidence) is that, bipedalism aside, we're still apes. We have fourth molars that don't fit in our mouths. Why? 'Cause apes have them. Our jaws have shrunk over the millennia, but the number of teeth hasn't.
I got to thinking about that after my "dental fun" entry. Fifty-thousand years ago, there was an advantage to not growing a fourth set of molars -- you wouldn't wind up with misaligned teeth and a fair amount of pain. Now, with dental surgery we can solve the problem easily. In the caveman days, a near-sighted hunter wouldn't be much use. Other members of his tribe/clan would take care of him, but since he'd be basically useless he probably wouldn't have much of a chance to mate. Now we have glasses, and some of us think that people who wear them look smarter.
Which lead me to this: Have we stopped human evolution? Since we can correct so many imperfections, there's no selection pressure for or against -- a diabetic has just as great a chance of having children as a non-diabetic. Would any genetic aberration allow a person a better chance to reproduce? In x millions of years, will we still be Homo sapiens sapiens?
Will it matter if we still are? After all, we've reached the point where we can adapt our environment to suit us, not the other way 'round, at least to a degree.
Or, what if we start trying to steer evolution? Shutting off the gene that makes wisdom teeth doesn't seem like a bad idea, and I don't think there would be any arguments about counteracting sickle-cell anemia, but where's a good place to stop? Is making a world full of Yao Ming-sized people OK? Or people who can metabolize food quickly and thus aren't as likely to become overweight?
Let's go farther: What if we could add in the genes that allow chameleons to blend in with their surroundings. I bet the Marines would love that. We could add the antifreeze compound that some species have that keeps their tissues from becoming damaged when they're frozen -- imagine the boon that would be to cryogenics. What if parents who wanted to raise a master piano player could deliberately cause polydactylism -- perfect for some whacked-out chords.
How far could we go, and still consider ourselves human? Are we human if that's the base model we start with, regardless of how much futzing we do? Are we human as long as we can create non-sterile offspring with some baseline, archetypical human? Who gets to define what the archetype is? If we could find a way to repair the chromosomal damage caused by mitosis that leads to aging, we could basically become immortal. Would it even matter then?
As always seems to happen when I get philosophical, I have no clue. We don't even have to worry about it for quite a while, since screwing around with DNA is currently limited to lesser lifeforms like E. coli and lab rats. But one day we'll have to figure it out.