Carl Zimmer in The New York Times:
A common genetic mutation is linked to an increase in life span of about 10 years among men, researchers reported on Friday. The mutation, described in the journal Science Advances, did not seem to have any effect on women. Still, it joins a short list of gene variants shown to influence human longevity. By studying these genes, scientists may be able to design drugs to mimic their effects and slow aging. But the search for them has been slow and hard.
When it comes to how long we live, nurture holds powerful sway over nature. In 1875, for example, life expectancy in Germany was less than 39 years; today it is over 80. Germans didn’t gain those extra decades because of evolving, life-extending changes in their genes. Instead, they gained access to clean water, modern medicine and other life-protecting measures. Nevertheless, heredity clearly plays a modest role in how long people live. For example, a number of studies have shown that identical twins, who share the same genes, tend to have more similar life spans than fraternal twins. In a 2001 study of Amish farmers in Pennsylvania, researchers found that close relatives were more likely to live to similar ages than distant ones. The impact of heredity on life span has turned out to be about as big as its influence on developing high blood pressure. But large-scale surveys of people’s DNA have revealed few genes with a clear influence on longevity. “It’s been a real disappointment,” said Nir Barzilai, a geneticist at Albert Einstein College of Medicine. Researchers are having better luck following clues from basic biology. In many species, for example, there is a relationship between an animal’s size and its life span. “If you look at dogs, flies, mice, whatever it is, smaller lives longer,” said Gil Atzmon, a geneticist at the University of Haifa in Israel who collaborates with Dr. Barzilai.