Amita Sehgal, a neurobiologist at the University of Pennsylvania in Philadelphia, has dubbed the gene whose mutation causes this effect 'Sleepless'.
She has revealed that this gene controls how brain cells fire, and that her study suggests that sleep is caused by a slowdown in certain neurons.
She believes that an inability to control such neurons may spell a restless night for animals besides flies.
''When you're having a bad night of insomnia you do have the need to sleep, but you're not able to. That might be what's going on with these animals,'' New Scientist magazine quoted her as saying.
Amita has discovered that flies with a broken copy of the Sleepless gene sleep quite lesser than the normal snooze period of about 12 hours a day, and that mutant insects don't seem to need to make up for lost sleep.
''When you deprive them, you're not really taking away any sleep, because there wasn't any to begin with,'' Sehgal says.
However, sleep deprivation shortens lifespan and impair co-ordination amongst mutant flies, she says.
''If one of us had insomnia and wanted to sleep but couldn't, we might stagger around a little bit,'' she adds.
Sehgal also found that the sleep deprived flies reflexively kept shaking their legs when knocked out with ether, an effect reminiscent of another gene mutation known to influence sleep patterns by regulating cell communication.
She hypothesizes that Sleepless monitors a brain cell slow-down that may be the very essence of sleep, and that neural activity goes haywire when the gene is not working properly, hence the constantly twitching legs.
A person does not go completely brain dead while having a nap, but Sehgal thinks that sleep comes when a small but critical number of brain cells slow down.
''This is a really major step forward for the sleep field,'' says Ravi Allada, a neurobiologist at Northwestern University in Evanston, Illinois.
Paul Shaw, a neurobiologist at Washington University in St. Louis, agrees that mutations like Sleepless can help explain the biology of sleep.
He, however, also feels that just because a gene mutation makes a fly sleep less does not mean that the gene causes sleep, and that scientists need to examine other characteristics affected by lack of sleep, such as learning.
An article on this research has been published in the journal Science.