What keeps you awake during the day (besides coffee) and sleepy at night? For life on Earth, it's a biological clock tuned to patterns known as circadian rhythms. And this year's Nobel Prize in Physiology or Medicine honors three American researchers who figured out just how that clock works.
Life on Earth has evolved to stay in sync with our planet's cycle of night and day. Our bodies anticipate this daily rhythm and regulate hormones, body temperature and even metabolism in accordance with the 24-hour cycle, writes Gina Kolata for the New York Times. This cycle's complexity and effects are most apparent when they get out of sync, like when you suffer from jet lag.
This year's first Nobel awardees, Jeffrey Hall, Michael Rosbash and Michael W. Young, have been puzzling over the circadian rhythm since 1984, reports Ariana Eunjung Cha for the Washington Post. Their work began with the isolation of a gene in fruit flies that directly controls the circadian rhythms for the bugs. Dubbed "period," this gene codes for a protein which changes concentration in tune with the creature's daily cycles.
The protein, called PER, builds up while the organism is resting at night, blocking the activity of the gene. Then during the day, the protein degrades. This cycle serves as a clock for the body, Hall and Rosbash found.
But how the gene blocked the activity of "period" remained unknown until Young, working independently, identified a second gene dubbed "timeless." This gene helped PER access the cell's nucleus and block the "period" gene's activity, reports Nicola Davis and Ian Sample of the Guardian. He also identified a third gene dubbed "doubletime," writes Eunjung Cha, which helps control the length of the cycles.
Research in the mechanics of circadian biology has gained new urgency in recent years, the Nobel Assembly note in a statement about the prize, as doctors and scientists have begun to understand how important not just the amounts, but the patterns of sleep are for a person's health. People who consistently live out of sync with their circadian rhythms, such as night-shift workers or frequent travelers, can have increased risks of becoming ill. Other researchers have already begun work on ways to "reset" an organism's circadian rhythm to correct these misalignments, for example.
“We are learning more and more what impact it has to not follow your clock,” Nobel committee member Christer Hoog tells Niklas Pollard and Ben Hirschler of Reuters. “If you constantly disobey your clock, what will happen?” Medical researchers are on a hunt to find answers.