Body clock secrets revealed

Mice and fruit flies appear to share the same body clock mechanism

Scientists have discovered some of the secrets of the biological clocks that govern the daily cycles of life.

They have found that the same system appears to operate across the animal kingdom.

Circadian clocks regulate daily activities such as sleep and wakefulness. Difficulty in readjusting the body clock causes jet lag and shift work problems, as well as some types of sleep disorders.

The clock may also explain why heart attacks occur more often in the morning and asthma flares up more often at night.

In two separate studies, reported in the journal Science, researchers have found remarkable similarities in the system used by mice and by fruit flies.

It is thought daily rhythms are controlled by switching specific genes on and off.

Researchers have identified circadian clock genes that are common to insects and mammals.

The new research indicates that the genes are regulated by a similar combination of two proteins in mice and fruit flies.

First evidence

Professor Joseph Takahashi, Head of Neurobiology and Physiology at Northwestern University in the US and a researcher on both studies, said: "We always thought that circadian clocks might work the same way in different organisms, but this is really the first evidence - with the same genes playing the same role in flies and mice.

"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."

Some neurobiologists believe that higher species evolved more specialised mechanisms built around an ancient "core oscillator." These accessories are thought to allow an organism to harness the clock to suit to its own needs and changing conditions of light.