Friday, January 8, 1999 Published at 15:13 GMT
What makes you tick?
The biological clock set ticking in the lab
The remarkable feat was achieved taking the part of a mouse's brain containing the clock nerves, keeping it alive in a petri dish and attaching electrodes to it. The regular electrical impulses with which the clock marks the rhythm of each day were then converted into sound.
"We hope that if we understand the mechanism of the biological clock it will enable us to design pharmacological treatments to control the working of the biological clock.
Other useful results would be treatments for sleep disorders and jet lag.
The research has uncovered how the biological clock works, as another team member, Professor Michael Young at Rockefeller University, explains.
This starts to slow the production proteins and re-absorb the fused proteins.
By noon the next day all the proteins have gone, and the cycle starts again.
Most biological research on body clocks has been done on animals, but the same genes control the clock in every animal ever studied, suggesting humans will not be an exception.
The location of the biological clock in the brain was determined by a transplant operation, performed by another group of scientists. They took the clock nerve cells from one hamster and transplanted them into a hamster born without these cells. The result was a hamster that knew to sleep at night and wake in the morning, a pattern missing before.
The work is featured in a BBC Science documentary, What makes us tick?, broadcast in the UK on Saturday, 9 January, at 1850 on BBC Two.