Human longevity hopes are raised by worm-gene study [EDIT: The Baby Boom sell-off is still coming]
world.scmp.com
Saturday, October 26, 2002
AGENCE FRANCE-PRESSE in Washington
The doubling of a worm's lifespan after American researchers modified its genetic make-up is being hailed by scientists as a breakthrough in the bid to increase human longevity.
University of California in San Francisco (UCSF) researchers said the breakthrough centred on the fact that the change in genetic composition avoided the usual side effect of removing the worm's reproductive capacity.
The technique involved modifying genes that control hormonal activity and that are common to many species including man.
The technique, tested on a millimetre-long worm, deactivates clusters of genes at different stages of the worm's growth to study their effects on longevity.
In previous work, they had shown that partial deactivation of the Daf-2 gene made it possible to double the worm's lifespan.
The gene encoded an insulin receiver as well as a hormonal growth promoter.
Other studies showed the influence of this hormonal production factor on the lifespan of the mouse and the fruit fly, which could make it equally important for man.
The Daf-2 gene also affects reproductive capacity but new research shows that the gene acts in various ways at various stages of life to control reproduction or longevity. This made it possible for scientists to separate these two functions, explained Cynthia Kenyon, a professor at UCSF.
"A lot of evolutionary biologists predicted that you couldn't lengthen life span without inhibiting reproduction," Professor Kenyon said in Science magazine.
"But that's not true. These worms live much longer than normal and they reproduce perfectly normally. They look great, they're vigorous.
"As we uncover more about how these and related genes function we hope to learn how youthfulness and longevity can be extended in humans without any side effects as well."
Her team discovered that if the Daf-2 gene is deactivated right after birth, the worms live twice as long but reproduce poorly.
On the other hand, if this gene is deactivated at the beginning of adulthood, the worms will live longer and reproduce normally.
Professor Kenyon and her team first discovered the effect of the Daf-2 gene in 1993, when they succeeded for the first time in increasing the lifespan of a living organism by genetic engineering.
The lifespan of the small worm is normally 15 days. |
