Walking and talking get more difficult for my mother every day, and when I phoned to tell her the headline of this story, there was a long pause before she found the words to reply: "I don't recommend it."

At 75, she is fighting one of the innumerable syndromes that elderly flesh is heir to. For reasons that no neurologist can explain, many of her brain cells are filling with debris called Lewy bodies. Her symptoms resemble those of Alzheimer's, and like Alzheimer's, the condition is sometimes genetic. Do we have to grow old so sadly? Before we go, do we have to lose most of the natural gifts that make life worth living? We are the first people in human history for whom this is a primary concern. For every generation before ours, the first concerns were Can I grow old? Will my baby reach a ripe old age? Please let us grow older! Now the average life expectancy in the U.S. has advanced from 47 in 1900 to better than 76 in 1999. During the next century, new biological discoveries should ensure that even more of us will live to see old age and will encourage us to dream, in wild or wistful moments, that we might not have to grow old at all.

Whenever I want to feel optimistic, I think about work in progress in the laboratory of Seymour Benzer of the California Institute of Technology. Benzer made the first detailed map of a gene's interior, and he and his student Ronald Konopka discovered the first so-called clock gene, which ticks away inside virtually every living cell, helping tell our bodies where we are in the daily sweep from morning to night. Now, at 77, Benzer is searching through our genes for a sort of clock of clocks that tells us where we are in the sweep from the cradle to the grave and decides how fast we age. Recently he discovered a mutant fruit fly that lives more than 100 days, about one-third longer than the rest of the madding crowd in a fly bottle. What makes the difference is a single gene, which Benzer calls Methuselah.

If one gene can do that much for flies (or worms or mice--genetic engineering has created a growing zoo of Methuselahs), then what can our genes do for us? Maybe there really is a clock of clocks, and maybe, just maybe, 21st century biologists will figure out how to twiddle and reset the hands. They might concoct Methuselah pills or inject Methuselah genes into fertilized eggs and fool our mortal bodies into believing that we are forever young. "Perhaps," Benzer muses, "aging can be better described not as a clock but as a scenario, which we can hope to edit." If we died in old age at the same rate we die between ages 10 and 15, then most of us in the U.S. would live 1,200 years. We would outdo the first Methuselah, whose years were 969. MORE>>

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