Scientists say they've found a clue to understanding why aging occurs in the body, and that this could help better understand -- and combat -- aging in humans. Two scientists from Northwestern University, Illinois, found a marker in the cells of the transparent roundworm, C. Elegans, which abruptly begins aging the worm's cells once it reached reproductive maturity.

The researchers found a simple genetic "switch" that began the aging process by turning off a cell stress response that protects vital proteins. The switch is activated in early adulthood, after the roundworm reaches sexual maturity, eight hours into its lifespan, ensuring that its future generation has a higher chance of living.

Previously, scientists thought that aging occurred due to a set of different factors, which would have to be addressed together in order to ensure longevity. However, they found that in the roundworm, a germline stem cell responsible for creating eggs and sperm automatically began the aging process once its job was done.

"C. elegans has told us that aging is not a continuum of various events, which a lot of people thought it was," senior author Richard Morimoto said in a press release. "All these stress pathways that insure robustness of tissue function are essential for life, so it was unexpected that a genetic switch is literally thrown eight hours into adulthood, leading to the simultaneous repression of the heat shock response and other cell stress responses."

The researchers said the genetic switch is present in all animals, including humans, which meant that the research had implications for future study of human aging as well. Their findings were published Thursday in the journal Molecular Cell.

"Wouldn't it be better for society if people could be healthy and productive for a longer period during their lifetime?" Morimoto said in the statement. "I am very interested in keeping the quality control systems optimal as long as we can, and now we have a target. Our findings suggest there should be a way to turn this genetic switch back on and protect our aging cells by increasing their ability to resist stress."