WASHINGTON, Nov. 8 (UPI) -- Whether people sleep a little or a lot can depend on a specific gene variation in human DNA, German researchers say.
Geneticists from the University of Munich scanned the DNA of more than 4,000 Europeans in a search for genes linked to a person's average sleep time, ScienceNews.org reported.
The researchers found that people with one variation of a gene called SUR2 tend to sleep 28 minutes longer than people with a different variation of the gene.
The gene encodes a protein that forms part of a channel that transports potassium in and out of cells, Karla Allebrandt of the Munich university reported at the annual meeting of the American Society of Human Genetics.
This is the second genetic variation found to affect sleep times.
Researchers from the University of California, San Francisco, reported last year that a rare variation in a gene involved in regulating the body's daily rhythms is linked with sleeping almost two hours a night less than average, SciencesNews.org said.