Sleep is a not a very well understood physiological process. During the day we are awake and active, but at night we become lethargic and groggy until eventually we fall asleep and the cycle repeats itself. This would lead you, and pretty much everyone else, to believe that sleep is controlled via pathways pertaining to the circadian clock. While this definitely appears to be a large part of what makes us sleep, apparently, it’s not the only part.
Researchers at Rockefeller University claim to have found a gene responsible for sleep in fruit flies. Through infrared technology, researchers were able to see when flies were sleeping and use this information to find sleep-deprived mutants. Comparison between normal-sleeping flies and sleep-deprived flies revealed a gene that may be responsible for this anomaly. This gene, called insomniac, was found to have a profound effect on the amount of time spent sleeping per day. Flies lacking the gene slept for 317 minutes a day compared to the average 927 minutes a day.
This might not seem particularly interesting, but the researchers also believe that insomniac is controlled by a homeostatic pathway, specifically a protein degradation pathway. What this means is that this gene affects the body regardless of the time of day, unlike in circadian mechanisms. Without this gene flies lived only two-thirds as long as their normal counterparts.
Article: http://www.sciencedaily.com/releases/2012/02/120220211013.htm