Sunday, March 04, 2007

3/4/07 Eyes

It was a lot harder to get these pictures than I thought, and I'm still not happy with them, but here they are. All five of us have different-colored eyes, though the photo-taking revealed that mine and Julian's are more similar than I'd thought.

Dad. Straight-on pure blue:

Mom. Dark grayish-drabish green around the edges, brown around the pupil:

Gabriel. Straight-on pure brown:

Julian. Dark grayish-blueish, with brown around the pupil:

Katrina. Bluish-grayish, most similar to Uncle Ronan:

What I really get out of this exercise is: Don't take closeups of grownups' faces and put them next to kids' faces, it'll peg your vanity meter.

Here's what I learned in high school about eye color genetics. Each person carries two eye color genes, one from each parent. A brown gene is dominant -- if you have one, it will override your other gene, and your eyes will be brown. So, brown+brown = brown, and brown+blue = brown. The only way to have blue eyes is have two blue genes (blue+blue = blue).

So how is it that two parents with brown eyes can have a blue-eyed child? If you're brown+blue, your eyes will be brown, but you can pass that blue gene on to your child. If your child's other gene from the other parent is also blue, then he'll have blue eyes. If both parents have blue eyes, then no one has any brown gene and everyone has blue eyes. Probably. It's really not that straightforward. I'm told that a brown-eyed child from two blue-eyed parents is possible but rare. More likely, geneticists are covering up for the milkman.

Of course, this is a gross and crude oversimplification of the complex science of eye color genetics. And of course there's much more than brown and blue -- indeed, just in our family of five, only Dave and Gabriel have clearly brown or blue eyes.

But if you believe these basics, for us to have a son with brown eyes means I do have a brown gene, and hence, brown eyes, even though my eyes don't look entirely brown like Gabriel's. I wonder if Julian is the same way. All three of our kids could have offspring with blue eyes, since they all carry a blue gene from Dave.

Congratulations to any of you who are still reading this. Forgive me this strange fascination. It's not the only one, I'm sorry to say, but I'll try to spare you my handedness-orientation ramblings for a few months.


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