What if exceptionally long life could be brought about with a single genetic mutation? In a few very simple species, that appears to be the case, and molecular biologists are exploring ways to parlay that knowledge into something that could benefit humans.
In a blockbuster discovery last year, scientists at the University of Washington found a group of genes that seem to affect roundworms' life span through activation of the hypoxic response, a biological defense against low-oxygen environments. Matt Kaeberlein and his colleagues engineered the worms to have the response turned on at all times, even when there was plenty of oxygen. Result: they lived longer and were healthier. It's not clear why that worked or whether it would have the same effect in mammals, but Kaeberlein believes the hypoxic response may encourage cells to metabolize more glucose. It may also enhance resistance to stress in some way.
The more such longevity genes that researchers have in hand, the more they can test to see if they work roughly the same way up the chain of lab-organism complexity, from yeast to fruit flies to mice and finally to us. "A lot of genes have been identified that when you perturb their function, you get increased life span," Kaeberlein says. The challenge is finding ones that will work in humans something that may not happen soon but, Kaeberlein believes, is likely in the future. "There's good reason for optimism," he says.