Neanderthal Genes Linked to Being a Morning Person

Early to bed, early to rise? Your genetic makeup might be a surprise. Researchers studying hundreds of genes that influence the body clock say people with some Neanderthal or Denisovan genes were much more likely to self-report being "morning people," the Guardian reports. When modern humans expanded out of Africa around 40,000 years ago, they encountered—and mated with—Neanderthals and Denisovans descended from populations that had moved to higher latitudes hundreds of thousands of years earlier. Researchers believe the groups modern humans met had adapted to an environment where the length of the day varied much more than it did in tropical Africa, the New York Times reports.

"We've found many Neanderthal variants that consistently associate with a propensity for being a morning person," says study co-author John Capra, per the Wall Street Journal. "Their effects are in the context of hundreds of other genes, but it is suggestive there is something meaningful about this." Capra, a geneticist at the University of California-San Francisco, says previous research has found that early risers are quicker to adapt to changes in the length of sunlight in a day. "We don't think that being a morning person is actually what was beneficial," he says, per the Guardian. "Rather, we think it is a signal of having a faster running clock that is better able to adapt to seasonal variation in light level."

The researchers used the UK Biobank, a database with genetic information on half a million British volunteers. Capra says the team is now looking at information on other populations, the Times reports. He hopes that if similar links between ancient genes and being a morning person are found, it could help doctors and scientists find ways to counteract disruptions to natural sleep cycles caused by night shifts and light from electronic devices. "In modern environments we are really beginning to appreciate how detrimental to our health it can be to be misaligned with our environmental light-dark cues," Capra says, per the Journal. (More Neanderthals stories.)