I’m standing in for Ethan Zuckerman, blogging from TED today. This post is part of a series from the TED 2009 conference held in Long Beach, California from February 4-8th. You can read other posts in the series here, and the TED site will release video from the talk in the coming weeks or months. Because I’m putting these posts together very quickly, I will get things wrong, will misspell names and bungle details. Please feel free to use the comments thread on this post to offer corrections. You may also want to follow the conference via Twitter or through other blogs tagged as TED2009 on Technorati.
Nina Jablonski is author of Skin: A Natural History, a close look at human skin’s many remarkable traits: its colors, its sweatiness, the fact that we decorate it.
She dives into the life of Darwin. Specifically, she is talking about human skin pigmentation. Darwin rejected the idea that skin color was determined by the sun, the environment. Nina states: “if only he lived today, If only Darwin had NASA.”
What Darwin didn’t appreciate, was that there was a fundamental relationship between ultraviolet radiation from the sun and people’s skin color. She shows a map of the predicted skin color derived from multiple regression analysis.
Darkly pigmented skin is highly protective under intense UVR areas, melanin is a natural sunscreen. She states that as people moved around the world, from high UV to low UV areas, there were skin color repercussions.
On how the globalization of travel (example: a white African’s like me, living in Sudan as a kid) : “We are living in environments where our skin pigmentation is not properly adapted.” There are both health and social consequences.
February 15, 2009 at 7:55 pm
In addition to the selection in favor of melanin for sun protection, I have heard it theorized that low melanin is selected for in northern lands because of a need for vitamin D. Equatorial peoples would get sufficient sunlight for vitamin D activation even with some some blocked while those up north would need more.
I have also heard that folic acid is light sensitive so southern peoples would derive a benefit from protecting it from the sun.
But arguing against the primacy of light is the claim that the melanin granules provide some anti bacterial and ant parasite properties which would be very useful in tropical regions like Africa.
It will be interesting to see how long-term immigration and modern travel alter racial compositions. If the advantages of specific skin colours to certain regions are strong enough they might keep being selected for and any lull in immigration would return each region towards its former skin tone even while unseen racial traits like blood antigens and such are altered completely in prevalence.
February 15, 2009 at 7:57 pm
Should read that “melanin granules provide some anti bacterial and ant parasite properties”. {:-)
February 15, 2009 at 7:58 pm
Crap I didn’t fix it right then either! You know what I mean. 😛
July 31, 2009 at 10:10 am
Ant parasite properties is what I am taking home with me!
Seriously, a primatologist friend was saying that for example, swahili women at the coast who cover themselves up totally with a ‘burkha’ are a modern day example and (if I remember the conversation correctly) the women will soon suffer from a vitamin D (or was is B?) deficiency and this will in many generations to come, affect the pelvis …. basically, survival of the fittest and they will have effectively taken themselves out of the ‘race’ . bigger brains and having to be born earlier and be helpless (not like other mammals where the young are born able to fend for themselves immediately) and eating fish so you adapt to move over the 45th parallel ….. but then swahili women live by the coast and eat fish so would that then, not protect them from rickets, even as they loose melanin… and I become more lost as I explain myself and this is what happens when an accountant speaks with a primatologist.