Some lucky people don’t groan awake to the alarm clock when they’ve only gotten six hours of sleep–instead they pop out of bed, bright-eyed and invigorated and ready for a new day. Now, researchers investigating the phenomenon of people who don’t need as much sleep as the rest of us have found a rare genetic mutation that accounts for some cases of shortened sleep cycles.
The scientists were searching the samples for variations in several genes thought to be related to the sleep cycle. In what amounts to finding a needle in a haystack, they spotted two DNA samples with abnormal copies of a gene called DEC2, which is known to affect circadian rhythms [The New York Times]. When they looked up the volunteers who had given the two DNA samples, they found a mother and daughter who habitually get about six hours of sleep each night and report no ...
