By Mike Fahey

Scientist Pinpoint The Clock Inside Every Living Thing, Even You

Inside every living creature there's a 24-hour clock that regulates the biochemical, physiological, or behavioral processes going on inside of us, and now scientists have discovered exactly what that clock is.

We call the 24-hour cycle that exists inside all living things on the planet the circadian rhythm. This rhythm can be seen in our sleeping and eating patterns, in cell regeneration, and our reactions to the cycling of day and night. The rhythm is present in every cell of every living thing.

Disrupt these rhythms and problems occur. Jet lag is probably the most commonly experienced phenomenon associated with disruption of circadian rhythms. Bipolar disorder is linked to circadian rhythms, and prolonged disruption has been linked to a greater chance of developing cancer.

Doctors might be able to fix problems arising from circadian disruption, but first they need to know where these rhythms originate from. Now we know, thanks to two new scientific studies.

A popular theory was that the rhythms originated in DNA. A study at the Institute of Metabolic Science at the University of Cambridge has blown that idea out of the water by identifying evidence of 24-hour rhythms in red blood cells. See, red blood cells don't contain DNA, so DNA definitely isn't the source of our internal clocks.

For the study, the scientists, funded by the Wellcome Trust, incubated purified red blood cells from healthy volunteers in the dark and at body temperature, and sampled them at regular intervals for several days. They then examined the levels of biochemical markers - proteins called peroxiredoxins - that are produced in high levels in blood and found that they underwent a 24-hour cycle. Peroxiredoxins are found in virtually all known organisms.

Eureka! These peroxiredoxins are the common mechanism maintaining our internal clocks, and they've been doing it for billions of years.

Another study, performed by the Universities of Edinburgh and Cambridge, and the Observatoire Oceanologique in Banyuls, France, examined the 24-hour cycle of marine algae, one of the planet's most ancient forms of life. Researchers tracked the peroxiredoxin levels in the algae over the course of several days. Even when the algae was in total darkness and its DNA inactive, the 24-hour rhythm was present.

Andrew Millar of the University of Edinburgh's School of Biological Sciences, who led the study, said: "This groundbreaking research shows that body clocks are ancient mechanisms that have stayed with us through a billion years of evolution. They must be far more important and sophisticated than we previously realised. 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."

And once we know what role these clocks play, we'll know how to fix them when they go wrong.

Ancient body clock discovered that helps to keep all living things on time [Cambridge University]