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July 25, 2008

Stanford study of aging supports developmental drift model: If right gene therapy is the main anti-aging weapon

A Stanford study of the aging of the C elegans worm does not support he accumulated chemical damage model of aging

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. If the Stanford study is correct and applicable to humans then periodic (every few decades) genetic engineering could be used to slow down or stop the effects of development drift aging. There have been a lot of recent progress towards genetic engineering and gene silencing. Adults with genetically caused blindness had eyesight improvement from gene therapy.

It is also possible that both mechanisms have an effect on aging, but that the developmental drift model may be more dominant. Fixing developmental drift could lengthen life spans by 2-4 times but using SENS against chemical damage would be needed for even longer lifespans.

"The take-home message is that aging can be slowed and managed by manipulating signaling circuits within cells," said Marc Tatar, PhD, a professor of biology and medicine at Brown University who was not involved in the research. "This is a new and potentially powerful circuit that has just been discovered for doing that."



key regulatory pathways optimized for youth have drifted off track in older animals. Natural selection can’t fix problems that arise late in the animals’ life spans, so the genetic pathways for aging become entrenched by mistake. Kim’s team refers to this slide as “developmental drift.”

“We found a normal developmental program that works in young animals, but becomes unbalanced as the worm gets older,” he said. “It accounts for the lion’s share of molecular differences between young and old worms.”

Kim can’t say for sure whether the same process of drift happens in humans, but said scientists can begin searching for this new aging mechanism now that it has been discovered in a model organism. And he said developmental drift makes a lot of sense as a reason why creatures get old.

“Everyone has assumed we age by rust,” Kim said. “But then how do you explain animals that don’t age?”

Some tortoises lay eggs at the age of 100, he points out. 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.


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