Monday, August 31, 2009

Deoxyribonucleic Acid


Bored one day, I decided to wet a few strands of hair that were sticking out of my coif to see what happened (a new and exciting experiment for me as I had spent so much of my life avoiding getting my hair wet). After saturating the strands, the most amazing thing happened: the hair transformed from a frizzy blob to almost perfect spirals resembling the double helix structure of DNA.

This got me thinking.

Not only is DNA the shape my hair resembles, but it is also the reason that it does (those narcissistic amino acids). So I thought I'd find out why curly, kinky, coiled, afro hair exists. After all, no other mammals have fur that resembles anything close to this (ok, fine maybe Alpacas and I think this is a whole other story, even though they can rock dreadlocks).

Michael Jackson (RIP) was wrong: you gotta blame this one on the sunshine! As pre-humans (Australopithecines and the like) were working their business out on the evolutionary treadmill so to speak, they were in Africa, right on the equator. Pretty much the hottest place in the world. Couple this blazing environment with being fully furred and beginning to take part in the athletic exertions of hunting, these little guys were really feeling the heat to adapt their bodies to this extreme climate.

While this head-to-toe fur blocked out UV rays (nature's SPF 80!), it also made physical activity in the direct, midday, sunlight less than pleasant. For us humans today, it would be like running a marathon, wearing an Ewok costume , in Cancun. But beneath that fur, these pre-humans had pale skin. So over time, they evolved darker skin, to protect them from damaging sun rays while being able to more efficiently sweat and cool their bodies, and on their heads curled, kinky hair.

Why this type of hair and not straight hair? Well, hair on our heads is kind of like a fiber optic cable: straight hair is the most efficient way to transmit UV rays to the scalp, whereas hair with a tightly wound S-shaped pattern will not. At all. So S-shaped hair it was for these pre-humans! This texture highly effective in keeping sun away from the scalp; they were not trying to fry their brains, they were trying to protect it so that they could evolve into a highly successful species that would eventually invent the internet so that I could share all of this with you!

If this equatorial oven really is the origin of ALL peoples' ancestry, shouldn't everyone technically have coarse, kinky, swirly, curly hair? Well, once upon a time their peoples probably did, but the reason not every one today has: once again, blame it on the sunshine! Vitamin D , created by our bodies in the absorption of UV rays is crucial for human health, so when groups of humans migrated north, out of Africa, where the sun is much weaker and less bountiful, to say, Scandinavia, humans needed to once again adapt their bodies, but this time to absorb as much UV as possible. How? With pale skin (no SPF 80 needed) and straight hair (highly effective fiber optic cable).

Today for persons of African descent living in not the sunniest or hottest places, in places like Minnesota or Northern California, kinky hair is more of a vestigial trait, or a remnant of what once was an survival necessity.

We are now lucky enough to be able to live in societies in which we can see the evolutionary grab bag that our species has become. The stuff that sits, hangs, and catapults from our heads is a real-time reminder of the science of evolution and, as I see it, a cause for celebration of our own ancestries. No longer isolated by geographic barriers, we are in the midst of the re-convergence of a multitude of diverse populations, where a person of Scandinavian descent may have set up shop in Ecuador or a Ghanian found home in Moscow. We are hopping right back on that evolutionary treadmill and it is and will continue to be fascinating to see how future generations adapt.