We humans are so much like flies. Our sleeping patterns are almost the same, according to a new study which has also identified a mutant gene enabling a minority of flies to sleep less than half the usual number of hours as their brethren. Chiara Cirelli, a University of Wisconsin psychiatrist who led the research team, now suspects a similar gene exists in humans, which may explain why a few of us can do an all-nighter, or regularly sleep three to four hours a night, without showing signs of sleep deprivation. 'Flies also sleep for many hours and, when sleep-deprived, show performance impairments,' wrote Dr Cirelli in the latest issue of the science weekly Nature. She recounts how her team subjected tens of thousands of flies to sleepless nights. Deprivation methods included generating high-frequency vibrations, increasing the temperature by 4 degrees Celsius every few minutes up to 44 degrees, and my favourite, rotating the box with flies inside so they either fell to their death from exhaustion or suffered a rude awakening. Those that showed no marked deterioration in motor skills were isolated and bred for several generations. The Wisconsin team then isolated in them a mutated gene appropriately called the Shaker since they were all shaken from their sleep. The university group now believes a human version of the fly gene enables some of us to require far less sleep than most others. The research was funded by the US Defence Advanced Research Projects Agency, the legendary but mysterious group that invented the internet and is part of the US Department of Defence. We are not sure if the Pentagon was interested in Dr Cirelli's methods or her findings.