Evolution takes an unimaginably long time - so long that opponents refuse to believe it's possible, or that even the amount of time is possible. Progress is incredibly slow as random tiny mutations are screened over millions of years to discover which work best. Backsliding would be even worse - the only thing worse than using a hundred million years to optimize a regulatory protein would be accidentally undoing the work over the next hundred kilo-millenia. Now University of Oregon investigators have discovered a genetic ratchet which prevents such extremely anti-productive reversals.
"Everyone has assumed we age by rust. But how do you explain animals that don't age? Some tortoises lay eggs at the age of 100, there are whales that live to be 200 and clams that make it past 400 years."
Stuart Kim, PhD, Stanford University professor of developmental biology and genetics
A prevailing theory of aging has been challenged by Stanford University Medical School researchers. Their discovery contradicts the theory that aging is a buildup of tissue damage similar to rust. The Stanford findings suggest specific genetic instructions drive the process. If they are right, science might one day find ways of switching the signals off and halting or even reversing aging.