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Morning Lark or Night Owl? Genes Know

Jan. 28, 2008 -- Are you a "morning person" who shines early, or a "night person" who is sharper later in the day?

Chances are, you don't need a team of scientists to answer that question. But new research shows that your body clock may be wound, in part, by your genes.

European scientists studied skin cells from 11 "larks" (morning people) and 17 "owls" (night people). Overall, the skin cells reflected participants' "lark" or "owl" tendencies.

For instance, the researchers conducted a lab test in which they made the skin cells glow, in test tubes, in time with their natural circadian rhythm. The skin cells from the morning people faded a little earlier than the night people's skin cells.

Also, a certain body clock gene was more active in the night people, report the researchers, who includedprofessor Steven Brown, PhD, of the Laboratory of Chronobiology at Switzerland's University of Zurich.

But it's not all about biology.

Participants' skin cells didn't all behave exactly as predicted. They had a wide range of circadian rhythms. So Brown's team concludes that a person's behavior -- such as staying up until the wee hours or rising at dawn -- also affects whether they are morning people or night people.

The findings appear in this week's online early edition of Proceedings of the National Academy of Sciences.

(Are you a night owl or an early bird? Do your habits affect your family? Discuss it with others on WebMD's Health Cafe message board.)