Stockholm
US geneticists Jeffrey C Hall, Michael Rosbash and Michael W Young were awarded the Nobel Medicine Prize today for shedding light on the biological clock that governs the sleep-wake cycles of most living things.

The team’s work revealed the role of genes in setting the “circadian clock”, which regulates sleep and eating patterns, hormones and body temperature.

“Their discoveries explain how plants, animals and humans adapt their biological rhythm so that it is synchronised with the Earth’s revolutions,” the Nobel Assembly said. All life on Earth is tuned to the rotation of our planet.

Scientists have long known that living organisms, including humans, have an internal timekeeper that helps them anticipate and adapt to the rhythm of the day.

Hall, 72, Rosbash, 73, and Young, 68, “were able to peek inside our biological clock and elucidate its inner workings”, the Nobel jury said.

They identified genes that regulate the clock, and the mechanism by which light can synchronise it.

The circadian clock is what causes jetlag — what happens when our internal clock and external environment move out of sync as we change time zones. It also regulates sleep, critical for normal brain function. Circadian dysfunction has been linked to depression, bipolar disorder, cognitive function, memory formation and some neurological diseases. Studies have indicated that a chronic misalignment between our lifestyle and circadian clock — irregular shift work, for example — may be associated with an increased risk for cancer, neurodegenerative diseases, metabolic disorders and inflammation.

Scientists are working hard on methods to alter the rhythm of errant clocks as a means to “improve human health”, said the Nobel team.

Using the fruit fly as a model organism, this year’s laureates isolated a gene that controls the daily biological rhythm, called the period gene.

“They showed this gene encodes a protein that accumulates in the cell during the night and is then degraded during the day,” the Nobel team said. “Subsequently, they identified additional protein components, exposing the mechanism governing the self-sustaining clockwork inside the cell.” The trio will share $1.1 million.