A research, reported in Nature by scientists in the US, has come to the conclusion that the time we get up or the time we go to sleep is determined by a gene.

Studying the fruit fly Drosophila melanogaster, Northwestern University scientists in Evanston, Ill., state that the findings can be applied to other organisms, including humans. When the gene, named 'twenty four', is missing, the PER protein in the neurons of the brain, regulating the circadian rhythm, is impacted; and, when there is very little of this protein, the sleep-wake cycles get disturbed.

Dr. Ravi Allada who led the study remarked, "The flies without the twenty-four gene did not become much more active before dawn. The equivalent in humans would be someone who has trouble getting out of bed in the morning."