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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Tanning Ability Driven by Evolution
22 June 2010 4:18 pm
Sunbathers who bronze beautifully have natural selection to thank. Research published in the Proceedings of the National Academy of Sciences suggests that the ability to tan is a trait that evolved several times in mid-latitude regions, such as China and the Mediterranean, where the sun's intensity varies dramatically from season to season. If inhabitants of these regions had consistently dark skin, which blocks the sun's rays, they wouldn't have produced enough vitamin D in the winter. If they had consistently light skin, their bodies would have been robbed of folate, a light-sensitive vitamin essential for cell division and repair. Folate is especially important during pregnancy; too little can result in birth defects. Indeed, the researchers posit that sun-induced folate deficiency, rather than skin cancer or sunburn, was the driving force behind the evolution of dark skin and tanning.
See more ScienceShots.