Saturday, January 8, 2011

his fingers slipping from her hand

The longer I'm out of school, the fewer things I remember about the material I learned. I do remember one lecture from Biology 420, Evolutionary Biology, and since I don't have much else to do I will share it with you now.

We were talking about random mating. The professor asked if we could think of any examples of when humans participate in random mating. The first answer alluded to picking someone up at a bar, but depending on one's inebriation even that isn't completely random.

But guess what? Everyone that gets married is doing some random mating of some kind or other. Some may care but most don't look at toe length when considering a prospective spouse. As far as I've heard, none of my married friends tested each other for PTC tasting prior to getting hitched.

(I should call it random gene interaction? I don't know. That's a lot harder to quantify. Sticking with the awkward one.)

My personal favorite, though, is hairy knuckles. Or, rather, hair on the knuckle. Here's how you test your own (pictures may be added later, if I'm motivated enough):

1. Place your hands palms together, in the "praying" position.
2. Curl your fingers down until the fingernails of each hand are touching each other. This should put your second knuckle flat across the top.
3. Peer at these second knuckles. You may see some fine hairs (or not so fine, depending on your hairiness). Or you may not. Even if you only have one, that's enough for you to have the trait.

As soon as we learned that, I determined that this would not be an instance of random mating for me! As soon as I get engaged (perhaps even before) I will check my fiance's hand for hairs. This is important for our unborn children!

Turns out I'm heterozygous. (I called my parents after the lecture and had them check themselves, and my siblings.) Having hair on the knuckles is a dominant allele; not having them is recessive. One of my parents has them, one does not. That makes me heterozygous (one allele of each), and I have hair on my knuckles.

If my husband loves me enough, he might ask his parents and siblings whether they have hair on their second knuckle. We might find out from the beginning what his genotype is, and we can draw Punnett squares to predict our children. Or we might have to wait for kids to start showing up with their second knuckles intact to find out his genotype.

And the presence or absence of hair on the knuckles of my children will no longer be due to random mating, but ... carefully controlled experimenting? That's what I'll tell them. That's sure to be reassuring!

Well, the above is about the extent of my interest in genetics. Tiem for diffrunt career nao?

"St Stephen's Cross"

1 comment:

Chillygator said...

I had a friend quite a few years ago who had us do that test for one of her classes. That's the first time I started paying attention to hair on my hands. And it drove me nuts. now I just shave my hands and arms (o: Sorry to my kids, though!

floral