“Lark genes”: the habit of getting up early has been linked to Neanderthal DNA

Scientists have found that genes inherited from our prehistoric Neanderthal relatives increase the tendency to wake up early – which is beneficial in regions with short winter days.

People who go to bed early and rise early may have their ancient ancestors to thank for this habit—or at least the Neanderthals with whom their ancestors bred, scientists say.

According to The Guardian, researchers have found that DNA inherited from our bushy-browed cousins ​​may contribute to some people’s tendency to be early risers, allowing them to get up and go to bed earlier more comfortably than others.

While most of the genes that modern humans acquired through ancient interbreeding were weeded out by evolution, a small portion remained, most likely because they helped early modern humans adapt to their new environment as they left Africa for Eurasia.

“By analyzing fragments of Neanderthal DNA that were preserved in the genomes of modern humans, we discovered a striking trend,” says John Capra, an epidemiologist at the University of California, San Francisco. Many of them, he said, influenced the genes that control the modern human biological clock, in most cases “increasing the tendency to be a morning person.”

Waves of Homo sapiens migrated from Africa to Eurasia about 70,000 years ago, writes The Guardian. Upon arrival, they encountered Neanderthals, who had already adapted to life in a colder climate, having occupied the territory hundreds of thousands of years ago. Thanks to interbreeding between groups, humans living today carry up to 4% Neanderthal DNA, including genes related to skin pigmentation, hair, fat and immunity.

John Capra and his colleagues analyzed the DNA of modern humans and Neanderthals and found that different genetic variants were involved in the biological clocks, or circadian rhythms, of the two groups. Because the ancestors of modern humans mated with Neanderthals, it is possible that some people alive today carried Neanderthal variants, the scientists reasoned.

To check, the researchers turned to the British Biobank, which stores the genetic, health and lifestyle information of half a million people. Not only were many people carriers of the variants, but the genes were consistently associated with early awakening, the scientists write in Genome Biology and Evolution.

But you don’t need Neanderthal genes to be a morning person. Hundreds of different genes influence when people sleep and wake up, and there are many environmental and cultural factors. Overall, Neanderthal genes have only a small impact.

Capra suspects that many modern humans carry Neanderthal genes because they helped their ancestors adapt to life at higher latitudes. “We don’t think being a morning person was actually helpful. Rather, we think it signals faster clocks that are better able to adapt to seasonal variations in light levels, says Capra. “At higher latitudes, it is useful to have clocks that are more flexible and can be better adjusted to accommodate changing seasonal light levels.”

Professor Mark Maslin from University College London, who was not involved in the study, comments: “We now have genetic evidence that some of us are indeed early risers. When humans evolved in tropical Africa, days averaged 12 hours. Nowadays, hunter-gatherers only spend 30% of their waking time gathering food, so 12 hours is a lot of time. But the further north you go, the shorter the days become in winter, when food is especially scarce, so it makes sense for Neanderthals and humans to start gathering food as soon as there was some light to work with.”