Ever wondered why some people seem perky after just a few hours of sleep a night, while the rest of us slog our way through the morning even after a good rest? New research from the University of Wisconsin–Madison says the answer may be in our genes.

What the researchers wanted to know: Is there a gene that regulates the amount of sleep we need?

What they did: The researchers used fruit flies because they have similar sleep patterns to humans—long periods of sleeping and impaired performance when they are deprived of sleep. They screened the genes of 9,000 flies with different mutations and found one, a mutation designated minisleep, that caused the flies that had it to sleep less. They isolated this gene and studied the behavior of flies that carry it.

What they found: Whereas most flies sleep between nine and 15 hours a day, flies with the minisleep gene slept only four to five hours a day. The gene did not affect the rhythms of sleep; the flies slept at normal times and did not awake more frequently than other flies, they just did not sleep as long. In addition, when both normal flies and those with the minisleep gene were deprived of sleep, the flies with the minisleep gene performed better on physical tests, such as moving quickly away from a hot area, than normal sleep-deprived flies. However, on the down side, the flies with the minisleep gene also did not live as long as those with a normal version of that gene.

What it means to you: This study adds to research in both animals and humans showing that genetics play a role in when we sleep and how much rest we need. While a minisleep gene has not yet been identified in humans, this research opens up the possibility that such a gene exists. If scientists do find an equivalent gene in our species, one day they may be able to manipulate it so that people can function better on less sleep.

Caveats: Fruit flies may exhibit some of the same sleeping patterns as humans, but, of course, they're still not exactly like humans. If scientists do find a similar gene in people, it would still be a very long time before human sleep schedules could be genetically altered.

Find out more: The National Institute of Neurological Disorders and Stroke has a webpage describing how sleep benefits our bodies.

The American Academy of Sleep Medicine has tips for people who are having trouble sleeping or who just want to make sure they're getting good sleep.

Read the article: Cirelli, C. et al. "Reduced Sleep in Drosophila Shaker Mutants." Nature. April 28, 2005, Vol 434, No. 7037, pp. 1087-1092.

Abstract online: http://www.nature.com