Why do some people need less sleep? It’s in our genes, new research suggests

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Some people are genetically programmed to need less sleep than the rest of us, according to a new paper published this week in Science. A rare genetic mutation lets its carriers function happily and healthily even with hours less sleep each night than doctors normally recommend.

Image Source/Corbis

Image Source/Corbis

Researchers discovered the enviable gene variant after studying a family in which two members, a mother and a daughter, seemed to need much less daily rest than their close relatives. The women slept just 6.25 hours per night, while others in the family averaged 8.06 hours. The researchers then sequenced some genes they thought could be responsible, and discovered that both mom and daughter — unlike others in the family — had a never-before-seen mutation in a gene that’s known to affect circadian rhythms.

Next, to test whether that gene variant was really the cause of mom and daughter’s shortened sleep time (and not just some freak coincidence), the researchers genetically engineered a group of mice to express the newly found mutation. Sure enough, those mice had a typical activity period that’s more than an hour longer, on average, than that of a normal mice. The mutant mice also seemed to need less catch-up sleep than others after a period of sleep deprivation. 

The new findings give a fascinating insight into why humans vary so much in how long we sleep — with a good night’s shut-eye ranging anywhere from six hours to nine, depending on whom you ask. But the result can hardly explain everything. This new-found gene variant appears in just 1 in 60 families that were studied, according to a follow-up paper that’s also published this week in Science. For genes to explain the full range of human sleep needs, then, there would have to be other genes involved too.

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