How genes affect pigmentation
Skin color has long been used to distinguish between races, not least by white supremacists who claim pale-skinned people are genetically distinct from those with dark skin. But a new study has struck a powerful blow to that concept of race. Researchers at the University of Pennsylvania examined the DNA of nearly 1,600 people with a wide range of skin tones from 10 different ethnic groups in Africa. They pinpointed six genetic areas that account for 29 percent of the variation in pigmentation; some make the skin darker, others lighter. To their surprise, the researchers found that dark-skin genes weren’t specific to the African continent—they were present in populations around the world. Moreover, many of the genes arose 900,000 years ago, some 600,000 years before Homo sapiens evolved in Africa. This suggests people with light and dark skin have coexisted in the same areas for hundreds of thousands of years—and confirms that white people did not “evolve” from black people. Study author Sarah Tishkoff tells TheAtlantic .com that her research “really discredits the idea of a biological construct of race.”
Researchers from the University of Winchester in the U.K. interviewed 30 male college students about their romances and their “bromances,” and found several similarities between the two. The men said they discussed personal issues, shared secrets, and allowed themselves to be emotionally vulnerable with their bromance buddies. All but one even reported some cuddling. Besides sex, the thing the men reported lacking in a bromance was criticism: They found their male friends more forgiving and less judgmental than their female partners, enabling them to talk more honestly and openly about their health, fears, and desires. The researchers warn that bromances can undermine the bonds between couples, but suggest that in most cases, the benefits may outweigh the drawbacks. “If men are happy to talk about and discuss their health worries with their closest friends,” co-author Adam White tells LiveScience.com, “it may have therapeutic effects for reducing and managing a whole host of health-related concerns.”
that people lose two months of their life for every kilogram they are overweight, and seven years if they smoke 20 cigarettes a day. On the upside, smokers who quit can essentially claw back those lost years, and every additional year of schooling adds 11 months to a person’s life span. The study also identified two genes that affect longevity: One is linked to cholesterol levels and cuts life expectancy by about eight months; the other is connected to the body’s immune system and adds about six months. Co-author Peter Joshi says although genetics affects longevity, people have “even more influence” through their lifestyle choices.