2008-07-29 20:33:29 GMT 2008-07-30 04:33:29 (Beijing Time) Xinhua English
WASHINGTON, July 29 (Xinhua) -- Researchers at University of Pennsylvania reported on Tuesday that they identified a gene that controls sleep of fruit flies.
Fruit flies typically sleep 12 hours a day. The research team studied 3,500 fruit flies and found mutants that survived on little to no sleep -- one to two hours a day or none at all.
The sleepless flies had a mutation of a gene that researchers have named Sleepless. They believe the Sleepless gene encodes a protein that affects whether potassium ion channels in the brain stay open or closed.
When the channels are open, the brain is connected and working -- the fly is awake. When closed, the channel shuts down and the fly sleeps. The insomniac fruit flies had less of the Sleepless-produced protein.
The lack of sleep didn't come without consequences. The Sleepless fruit flies lived about half as long as fruit flies that did not carry the mutation. They also experience impaired coordination and restlessness in their few hours of sleep.
Sleep is regulated by two processes: circadian and homeostatic. Circadian regulation affects the timing of sleep, and the homeostatic mechanism affects the need for sleep. The Sleepless gene affects the homeostatic mechanism.
For human being, a sleep of six to eight hours every night is necessary. However, scientists have long been puzzled about what controls the actual need for sleep. Now, from the new gene, the research team might have an answer, at least in fruit flies.
Sleep has been observed in everything from flies to dogs to people, indicating that it's essential to life. Insufficient and poor-quality sleep is an increasing problem in industrialized nations. In the U.S. alone, about 70 million people suffer from chronic sleep problems.
"In the long term, we hope that human equivalents of our gene will be isolated and will not only further our understanding of human sleep, but perhaps also serve as drug targets to promote sleep or treat insomnia," says Amita Sehgal, the lead researcher.