Few of us would think we resemble fruit flies in our daily rhythms and habits, but one Penn investigator has used these familiar insects to uncover hidden secrets of the circadian clock.

In 2006, Amita Sehgal, PhD, professor of Neuroscience, discovered that a brain region previously known for its role in learning and memory also serves as the location of sleep regulation in fruit flies. Harnessing the power of Drosophila genetics, her team has also uncovered neurons and proteins that link basic clock information to daily behavior.

Although it’s not yet clear how these observations translate to human medicine, Sehgal’s team has found some interesting parallels between human and fly behavior. For example, Sehgal found that flies lacking the key clock gene Clock are active during the night, when they should be sleeping. That pattern resembles one seen in older people with dementia or other forms of cognitive impairment who experience agitation around sundown, as well as disruptions in their sleep-wake cycles. Working with the flies, Sehgal discovered that excess dopamine causes the problem. Whether that is the root of the problem in humans as well is unclear, but the observation does give physicians some hints about what might help these patients.

Whereas nutritionists often warn us not to eat late at night because it leads to weight gain, Sehgal found that flies tricked into eating late in the day were less fertile than their early-eating counterparts. Sehgal doesn’t know if a similar affect on fertility occurs in humans, but she says her fly data does show that altering the timing of food intake relative to sleep has a negative impact on both organisms’ physiology.

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