Age may not be rust after all. Specific genetic instructions drive aging in worms, report researchers at the Stanford University School of Medicine. Their discovery contradicts the prevailing theory that aging is a buildup of tissue damage akin to rust, and implies science might eventually halt or even reverse the ravages of age.
The “rust” the prevailing theory uses to explain aging is essentially the accumulated wear and tear caused by “toxins, free-radical molecules, DNA-damaging radiation, disease and stress.” But the results of the Stanford research, led by Stuart Kim, professor of developmental biology and of genetics, don’t fit that theory. Instead, they found that that hundreds of age-related genes in C. elegans nematode worms were switched on and off by a single transcription factor–a kind of signalling molecule–called elt-3, which becomes more abundant with age. Two other transcription factors that regulate elt-3 also changed with age. As a result, normal development becomes unbalanced in older organisms, something the researchers call “developmental drift.” And now that this mechanism has been found in one organism, scientists can look for it in others–including humans.
The idea that this developmental drift is behind aging rather than “rust” would explain why there are many animals that live far longer than humans:
Some tortoises lay eggs at the age of 100…There are whales that live to be 200, and clams that make it past 400. Those species use the same building blocks for their DNA, proteins and fats as humans, mice and nematode worms. The chemistry of the wear-and-tear process, including damage from oxygen free-radicals, should be the same in all cells, which makes it hard to explain why species have dramatically different life spans.
If aging is not a cost of unavoidable chemistry but is instead driven by changes in regulatory genes, the aging process may not be inevitable. It is at least theoretically possible to slow down or stop developmental drift.
Having just celebrated another birthday and thus entered my 50th year on this planet, I can only say, “Faster, please!”
(Image: Wikimedia Commons.)
[tags]aging, biology, genetics, immortality[/tags]