The sandman gene

Researchers find another genetic variant linked to sleep duration

WASHINGTON — Whether people sleep a lot or a little may depend in part on a gene that also determines whether fruit flies snooze all night. Geneticists studying sleep duration in people scanned the DNA of more than 4,200 Europeans, looking for genes associated with a person’s average nightly sleep time. The team found that people who have one version of a gene called SUR2 sleep about 28 minutes longer than people who have another version of the gene, said Karla Allebrandt of the University of Munich, who presented the research November 5 at the annual meeting of the American Society of Human Genetics. In order to determine whether SUR2 really affects sleep or was just found by coincidence, the researchers then examined the gene’s function in fruit flies. The team removed the gene from the brains of two strains of fruit flies and then recorded how well the flies slept. Flies without SUR2 didn’t sleep as long at night as flies that have it, Allebrandt said. The gene encodes a protein that forms part of a channel that transports potassium in and out of cells. Last year researchers from the University of California, San Francisco reported that a rare variation in DEC2 , a gene involved in regulating the body’s daily rhythms, is associated with sleeping almost two hours a night less than average ( SN: 9/12/10, p. 11 ).

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.