Interesting report. If confirmable, it wont come as a complete suprise to me.
Though not directly connected to the right to bear arms, the anxiety over skin shading has been exploited thoughout the United States for various reasons, including the wish to deprive certain otherwise law abiding people of their means to self defense.
It would be ironic if so much of this ethnic strife arose from a mere environmental adaption.
Jeff
sacbee: Cal Report
Address:http://www.sacbee.com/news/calreport/calrep_story.cgi?N112.HTML
Skin color is regional adaptation, scientists say
SAN FRANCISCO (AP) -- Two San Francisco scientists using data from a NASA satellite say they have discovered why people come in different colors.
Variations in human skin color are the result of adaptations to the amount of ultraviolet light from the sun falling on different regions of Earth, according to Nina Jablonski and George Chaplin, scientists with the California Academy of Science.
People's bodies change their skin color over time to let in just the right amount of UV light, which is key to having healthy babies.
UV light affects the skin's production of folate, part of the B vitamin complex, and vitamin D-3, both of which are essential for having healthy children.
Folate is necessary for the proper development of the nervous system in fetuses and for sperm production in adult males. Vitamin D-3 helps build and maintain strong bones and a healthy immune system.
But too much solar UV light can not only cause skin cancer, it can also damage those chemicals, thereby hurting a person's chances for reproductive success.
The scientists' finding may also explain why women tend to be lighter-skinned than men. Lighter skin lets in more solar UV light, increasing a woman's vitamin D-3 production, which helps the fetus grow during pregnancy and helps nourish newborns through breast feeding.
UV light from the sun varies from region to region for reasons including latitude, humidity and cloudiness.
Jablonski and Chaplin's discovery isn't entirely new. For a long time, scientists have thought there was a correlation between UV light and skin color, and they knew the light helped produce vitamin D and that it could cause cancer.
"But this explanation was considered weak by some scientists because skin cancer has little or no effect on people's ability to reproduce, which is really the bottom line of every evolutionary spreadsheet," Jablonski said.
Jablonski developed the hypothesis that links UV light to reproduction in 1991. The scientists analyzed published measurements of human skin color from around the world and data from NASA's Total Ozone Mapping Spectrometer satellite, which orbited Earth from 1978 to 1993 and gathered direct UV measurements for the entire globe, to find the correlation between skin color and UV light.
Jablonski and Chaplin found that dark skin acts as a natural sunscreen to help prevent UV light from breaking down folate, so it is helpful in areas with a lot of sun. But in less sunny areas, dark skin screens out too much sunlight, and can inhibit the production of vitamin D-3, so lighter skin is helpful for reproductive success.
Skin color is based on the level of melanin, an organic molecule with an undetermined chemical structure. Those with more melanin have darker skin, and melanin levels are genetic. But the variations in skin color are adaptations to solar UV light, not biological differences among people, according to Jablonski and Chaplin.
"We're all the same under the skin," Jablonski said.
Though not directly connected to the right to bear arms, the anxiety over skin shading has been exploited thoughout the United States for various reasons, including the wish to deprive certain otherwise law abiding people of their means to self defense.
It would be ironic if so much of this ethnic strife arose from a mere environmental adaption.
Jeff
sacbee: Cal Report
Address:http://www.sacbee.com/news/calreport/calrep_story.cgi?N112.HTML
Skin color is regional adaptation, scientists say
SAN FRANCISCO (AP) -- Two San Francisco scientists using data from a NASA satellite say they have discovered why people come in different colors.
Variations in human skin color are the result of adaptations to the amount of ultraviolet light from the sun falling on different regions of Earth, according to Nina Jablonski and George Chaplin, scientists with the California Academy of Science.
People's bodies change their skin color over time to let in just the right amount of UV light, which is key to having healthy babies.
UV light affects the skin's production of folate, part of the B vitamin complex, and vitamin D-3, both of which are essential for having healthy children.
Folate is necessary for the proper development of the nervous system in fetuses and for sperm production in adult males. Vitamin D-3 helps build and maintain strong bones and a healthy immune system.
But too much solar UV light can not only cause skin cancer, it can also damage those chemicals, thereby hurting a person's chances for reproductive success.
The scientists' finding may also explain why women tend to be lighter-skinned than men. Lighter skin lets in more solar UV light, increasing a woman's vitamin D-3 production, which helps the fetus grow during pregnancy and helps nourish newborns through breast feeding.
UV light from the sun varies from region to region for reasons including latitude, humidity and cloudiness.
Jablonski and Chaplin's discovery isn't entirely new. For a long time, scientists have thought there was a correlation between UV light and skin color, and they knew the light helped produce vitamin D and that it could cause cancer.
"But this explanation was considered weak by some scientists because skin cancer has little or no effect on people's ability to reproduce, which is really the bottom line of every evolutionary spreadsheet," Jablonski said.
Jablonski developed the hypothesis that links UV light to reproduction in 1991. The scientists analyzed published measurements of human skin color from around the world and data from NASA's Total Ozone Mapping Spectrometer satellite, which orbited Earth from 1978 to 1993 and gathered direct UV measurements for the entire globe, to find the correlation between skin color and UV light.
Jablonski and Chaplin found that dark skin acts as a natural sunscreen to help prevent UV light from breaking down folate, so it is helpful in areas with a lot of sun. But in less sunny areas, dark skin screens out too much sunlight, and can inhibit the production of vitamin D-3, so lighter skin is helpful for reproductive success.
Skin color is based on the level of melanin, an organic molecule with an undetermined chemical structure. Those with more melanin have darker skin, and melanin levels are genetic. But the variations in skin color are adaptations to solar UV light, not biological differences among people, according to Jablonski and Chaplin.
"We're all the same under the skin," Jablonski said.
. But if it hits 80deg. F outside, I'm not happy...at 100 I wanna die 
