In a recent issue of Science, one team describes the working parts that drive the clock in mice forward like a watch spring, and in another paper another team for the first time identifies the gene in fruit flies that corresponds to the mammalian Clock gene and shows how it can turn itself off again, enabling it to oscillate like a pendulum. These genes define a surprisingly simple and elegant feedback loop of gene activation and inhibition that composes the core mechanism of the clock in animals.
Circadian clocks regulate daily activities such as sleep and wakefulness.
Difficulty in readjusting our clocks causes jet lag and shift work problems, as well as some sleep disorders. The clock may also explain why heart attacks occur more often in the morning and asthma flare-ups more often at night. These accessories would allow an organism to harness the clock to suit to its own needs and changing conditions of light or temperature. The research at Northwes-tern was funded by the NSF Center for Biological Timing and the National Institutes of Health. Takahashi is a researcher in the Howard Hughes Medical Institute.