Scientists pinpoint ancient body clock

An internal 24-hour clock that affects all forms of life has been identified by University scientists. The research provides important insight into health-related problems linked to individuals with disrupted clocks - such as pilots and shift workers. The findings also indicate that the 24-hour circadian clock found in human cells dates back millions of years to early life on Earth. Daily rhythms. More work is needed to determine how and why these clocks developed in people - and most likely all other living things on earth - and what role they play in controlling our bodies. Professor Andrew Millar School of Biological Sciences Circadian clocks control many of our physiological functions, including our sleep cycles, hormone function and physical strength. Such clocks also control seasonal changes seen in nature, such as animal breeding patterns and plant growth.