Was background radiation somehow required for life?
The general rule is the less radiation exposure, the better: In this view, “There is no safe amount of radiation,” says New Mexico State University researcher Hugo Castillo.
You’d think that when you protect cells from the natural background radiation, they’d do better-no radiation means no stress, no damage, faster growth.
“But it appears the cells can turn some genes on and off to compensate for this lack of radiation.” Moving the microbes to the control incubator with more radiation erased both the growth problems and the change in gene regulation, confirming the connection with radiation.
If in the normal course of life cells are never struck by a radiation particle, how in the world does the presence or absence of such particles register? Perhaps the answer lies in incredibly swift and complete communication between cells.
“If the cells had been living for a few months in an environment in which the background radiation was normal,” says Massimo Pinto, a radiation scientist who worked on the experiments, “These cells were more ready to respond to an insult in the form of a challenge dose. The sister cells that had an artificially reduced background radiation level were not as capable.”
It’s a peculiar finding-why would being without radiation make cells more vulnerable? One theory is that very low doses of radiation can cause cells to keep their repair machinery switched on, and those without it are unprepared, like a runner who skipped one too many workouts before a marathon.