Two important studies have given scientists a new insight into the circadian clock, the biological mechanism that keeps all cells ticking on a twenty-four hour cycle.  The research overturns the prevailing idea that the biological clock works through DNA, leaving its true mechanism seeming even more mysterious. Research into the clocks could one day have important implications for understanding certain diseases such as diabetes and even cancer.Biologists have long known that our bodies work on an internal rhythm, which keeps the activity of cells synchronised with a 24-hour day. The clock controls processes across biology – it tells flowers when to open and migrating monarch butterflies navigate using the clock in their antennae as a sun compass. Seminal experiments have shown that humans will eat, sleep and wake in 24-hour cycles, even when they live in complete darkness and have lost track of time.In the latest research, Cambridge researchers have proved that even red blood cells have a circadian clock, by showing that they produce certain proteins, called peroxiredoxins, more at some times of day than others.  This discovery is a breakthrough because red blood cells do not contain DNA, and so the biological clock cannot work via DNA and gene activity, as had always been assumed.A second study, by researchers from Edinburgh and Cambridge Universities, demonstrated evidence of the circadian clock in marine algae.  Again, this was proved by showing that the levels of peroxiredoxins the alage produced varied cyclically. The finding is significant because algae are simple and primeval organisms and the circadian rhythms they exhibit must therefore have developed at an early stage in evolutionary history.  Dr Andrew Millar, 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.”The research highlights how little we know about the mechanisms of cellular rhythmicity. Out-of-sync circadian rhythms are associated with many diseases and it is hoped that a full understanding of the clocks will lead to improved treatments.  Dr Akhilesh Reddy, the Cambridge researcher who led one of the studies, said, “The implications of this for health are manifold. We already know that disrupted clocks – for example, caused by shift-work and jet-lag – are associated with metabolic disorders such as diabetes, mental health problems and even cancer. By furthering our knowledge of how the 24-hour clock in cells works, we hope that the links to these disorders...will be made clearer. This will...lead to new therapies that we couldn’t even have thought about a couple of years ago.”