If you were a nematode in Siegfried Hekimi's genetics lab, you would be one of the most remarkable creatures in the world. It wouldn't be your looks that made you special, of course. As a tiny transparent worm measuring a millimeter from tip to tail, you would be nearly invisible to the naked eye. Nor would it be the way you spent your time. Moving little and eating less, you would pass all your days inside a Petri dish, resting atop a bed of nutrient.
No, what would make you unique as you lived your unexceptional life would be how long you got to live it. Nematodes in Hekimi's laboratory at Montreal's McGill University have been known to survive for 50 days. Nematodes outside the lab survive for barely nine. A human being this long-lived would be 420 years old.
Across the continent, at the University of California at Irvine, evolutionary biologist Michael Rose has created a community of fruit flies almost 1 million strong. The fleck-size insects spend their time doing what fruit flies do: they eat, they breed, they fly. But they do it for a lot longer. Fruit flies in Rose's colony may survive for up to 140 days. In the absence of predators, fruit flies in the wild get just 70. A person with this kind of longevity would easily exceed 150 years.
For researchers studying aging--as well as for the rest of the human population, getting inexorably older and feeling none too happy about it--the rules have always been simple: organisms are born, they live a more or less prescribed number of years and they die. If you watch your weight, eat right and get plenty of exercise, you can perhaps negotiate the terms a bit, squeezing out a bit more time here and there. But tripling life-spans? Quadrupling life-spans? Eliminating the very idea of life-spans? Not an option.
Or so it seemed. But now the rules are quietly being broken. Hekimi and Rose are only two members of a growing community of scientists who have decided that the old way of thinking about senescence needs to be challenged. In laboratories around the world, investigators are beginning to suspect, to their growing surprise and excitement, that what works in flies and worms may work for people too. From species to species, genus to genus, the cellular mechanisms responsible for aging appear to be the same. Armed with that knowledge, a new breed of longevity specialists is beginning to tease out answers to two of the great mysteries of life: Why do we age? And even more important, What can we do about it?
The clues are tantalizing. In some research centers, investigators are studying an area at the tip of chromosomes that appears to shorten, fuselike, as we grow older. Extinguish the chemical fire that consumes the fuse, and you might be able to bring aging to a halt. Elsewhere, scientists are studying how the waste produced when a cell consumes food can contaminate its innards, a process that can lead to the body-wide breakdowns we associate with aging. Clean up the cells, and you should be able to buck up the entire organism. Still elsewhere, geneticists are beginning to map the very genes that direct us to get old in the first place. After mapping genes, the next logical step is manipulating them, and once you start reweaving the DNA that codes for life itself, anything is theoretically possible.