Women Sleeping
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An international team of researchers have reportedly discovered a gene that regulates how long a person needs to sleep, and could explain why some individuals seem to possess an internal alarm clock.

The research, led by chronobiologists Professor Till Roenneberg and Dr. Karla Allebrandt of the Ludwig Maximilians University (LMU) of Munich, could also explain why some individuals are light sleepers, able to stay active and thrive on just a few hours worth of slumber each night.

"Clearly, individuals vary with respect to how much sleep they need. Indeed, sleep duration is influenced by many factors," LMU representatives said in a press release Thursday. "Apart from seasonal and other variables, age and sex play a role, as does one's sleep-wake cycle or chronotype, i.e. whether one is a lark (early to bed, early to rise) or the converse, an owl."

They add that this research has "identified the first genetic variant that has a significant effect on sleep duration and is found frequently in the general population. The variant was discovered in the course of a so-called genome-wide association study, in which the researchers scanned individual genomes for variations that were correlated with sleep patterns."

According to the Daily Mail, the gene is called ABCC9 and has been nicknamed the "Thatcher gene" in honor of former British Prime Minister Margaret Thatcher, who famously is said to have governed on as little as four hours of sleep per evening.

The study looked at the sleeping habits of 4,000 subjects representing seven different European nations. Each participant was asked to fill out a questionnaire disclosing details about their sleeping habits, and the researchers then looked both at their answers and their genetic information.

As it turns out, the scientists discovered that those who had two copies of a common variant of the so-called Thatcher gene spent "significantly shorter" periods of time asleep than those with two copies of a different version of the same gene.

Having previously learned that the ABCC9 gene was also present in fruit flies, the researchers were able to modify it so that the length of time it spent asleep decreased, the Daily Mail added.

"Apparently the relationships of sleep duration with other conditions such as heart disease and diabetes can be in part explained by an underlying common molecular mechanism," Allebrandt told the UK newspaper. "The ABCC9 gene is evolutionarily ancient, as a similar gene is present in fruit flies. Fruit flies also exhibit sleep-like behavior... When we blocked the function of the ABCC9 homolog in the fly nervous system, the duration of nocturnal sleep was shortened."

"It is very encouraging for us that ABCC9 also affects the nocturnal sleep period in flies," Roenneberg added in a statement. "This tells us that the genetic control of sleep duration may well be based on similar mechanisms in a wide range of highly diverse species."