Long-Lived Worm Hints at Genetics of Aging
Strobel, Gabrielle, Science News
Who hasn't dreamed of extending his or her life span?
A lowly worm can do just that. The tiny nematode Caenorhabditis elegans more than doubles its normal life expectancy when carrying a mutation in a gene called daf-2, announce researchers at the University of California, San Francisco.
Equivalent in age to a 150-year-old person, the daf-2 mutants appear healthy until a few days before their demise, says developmental biologist Cynthia Kenyon. Adult, fertile daf-2 mutants feed and move normally for about 60 days, while wild-type, or normal, worms die at about 25 days, Kenyon and her co-workers report in the Dec. 2 NATURE.
"This study is the first clear demonstration that aging in this worm is not a random degeneration event but is regulated by identifiable genes," comments geneticist James H. Thomas of the University of Washington in Seattle.
"It was striking to see how much faster the wild-type worms [aged]," Kenyon says. "When the wild type aged, they lost their muscle tonus, looked flaccid and decrepit. At that time, the mutants still looked young and zipped around."
In normal nematodes, Kenyon says, the daf-2 gene acts as a brake on a second gene, daf-16, located further downstream in the DNA. In worms lacking daf-16, the daf-2 mutation does not prolong life, suggesting that both genes are involved in regulating the rate of aging.
That finding may give researchers a handle on unlocking the genetics of aging in mammals, Kenyon adds. "We'd like to find the counterparts [of daf-2 and daf-16] in mammals. …