Scientists studying the pattern of circadian rhythms have found that one central body clock could be controlling several others at the same time. By examining fruit flies - which, like humans, have several circadian clocks affecting the rhythm their daily biological processes - researchers have found evidence of a single 'master' clock that leads all other internal clocks related to sleeping and eating patterns, and various organ functions. The team says this finally gives experimental proof for the so-called coupled-oscillator model moderating the daily rhythms of our physiology and behaviour. "This is the first comprehensive experimental description of a pathway that links circadian clocks, and it shows that the coupled-oscillator model is actually true in certain cases," says one of the researchers, Christian Wegener from the University of Würzburg in Germany. The team focussed on a neuronal pathway (the hyperthetical master clock) that linked the circadian clock in the brain of the