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Not a morning person? Blame genetics. Researchers in England have identified several genes associated with the timing of peak activity. Most of us feel we are most alert or productive at particular times of day, and these genes may help determine when those times of day might be.

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The researchers worked with fruit flies, or Drosophila, commonly used research organisms since fruit flies have many analogous genes with mammals, coupled with a short generation time. It was only fairly recently, however, that scientists began using fruit flies to model the genetics of sleep.

The sleep genetics breakthrough came in 2000 when researchers discovered that fruit flies sleep. It was assumed that sleeping was a luxury reserved for mammals, birds, and some fish. Flies possess genes associated with circadian rhythms, but insects are so small and unsophisticated that nobody believed that insects truly needed sleep.

Unable to measure brainwaves in their miniscule brains, the scientists turned to videotape, and soon learned that fruit flies spend most nights keeled over and motionless except for a few twitches (no word on snoring or sleep-flying). It took a large disturbance to roust the flies, and caffeine administered before the flies’ bedtime kept the flies from sleeping soundly.

It might not be exactly like human sleep, but the flies’ activity was close enough that it launched genetic investigations into the mechanism of sleep. You know that friend who only seems to need a few hours of sleep a night? It turns out that flies with one particular mutation need far less sleep than their wild-type counterparts. In something out of a Drosophila spy movie, flies were deprived of sleep for 24 hours, and then put through a series of tests in avoiding danger, recognizing food, etc. The normal flies were much slower at these tasks after being sleep deprived, but those with the mutation were unaffected. This gene is also found in humans, so maybe your boastful friend is telling the truth.

We’re a very sight-dependent species, so it makes sense that our peak activity patterns have a genetic basis. We would not have lasted long in the savannah against predators if we were wide awake during the dangerous hours of darkness, deprived of our most vital sense. Those interested in workplace productivity might take note; perhaps in the future a genetic test will determine your optimal schedule. Tomorrow, if you oversleep the alarm, maybe blame your genes.


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Science News, Vol. 157, No. 8 (Feb. 19, 2000), p. 117
Society for Science & the Public
Science News, Vol. 167, No. 18 (Apr. 30, 2005), pp. 275-276
Society for Science & the Public