– Why some of us grumble in the morning – and others don’t
Scientists say people who go to bed early and wake up early may owe this habit to the Neanderthals whose ancestors bred it.
Researchers have discovered that the DNA we get from Neanderthals – A cousin on our family tree – Contributed to the fact that some people are more likely to wake up early and also find it easier to go to bed early than others.
While most of the genes acquired by modern humans through interbreeding in ancient times have been eliminated by evolution, a small percentage remains. “When we analyzed the parts of Neanderthal DNA that remained in the modern human genome, we discovered a surprising trend,” said John Capra, an epidemiologist at the University of California, San Francisco. Much of it has to do with genes that control the body’s internal clock (also called the “circadian rhythm”) in modern humans, and in most cases has led to “an increased tendency to be a morning person,” Capra said.
To test this, Capra and his team turned to a large British biobank that had data from half a million people. Not only did many people carry these variants, but the genes were also consistently linked to “early awakening,” the scientists wrote in the journal Genome Biology and Evolution.
Capra suspects that many modern humans carry Neanderthal genes because they helped their ancestors adapt to life at high latitudes. “We don’t think being a morning person was actually beneficial. Instead, we think it’s a signal of an internal clock that runs faster and can better adapt to seasonal fluctuations in light conditions,” Capra says.
Professor Mark Maslin from University College London, who was not involved in the study, provided an explanation for this to The Guardian. “Now we have genetic evidence that some of us are indeed morning people. When humans evolved in tropical Africa, the average day was 12 hours long. Today, hunter-gatherers spend only 30% of their waking hours gathering food, so 12 hours “It’s a long time. But the further north you go, the shorter the days become in winter, when food is particularly scarce. That’s why it makes sense that Neanderthals and humans would start gathering food as soon as there was light to work with.”
You don’t need Neanderthal genes to be a morning person
About 70,000 years ago, waves of Homo sapiens migrated from Africa to Eurasia. When they arrived, they encountered Neanderthals, who had already adapted to the cold climate after inhabiting the area hundreds of thousands of years ago. Thanks to interbreeding between the two groups, people living today carry up to 4% Neanderthal DNA, including genes associated with skin and hair pigmentation, fat and immunity.
In general, Neanderthal genes have only a minor effect on human sleep and wake time. Hundreds of different genes are responsible for this, but also many cultural and environmental influences.