Are you the type of person who wakes up early? This may be due to Neanderthal DNA

Are you someone who only jumps out of bed when the alarm rings? Do you go to bed early too?

Maybe you can thank Neanderthals for that.

You may have inherited some genes from them, our prehistoric ancestors.

At least that's the opinion of researchers who published a new study in the journal Genome Biology and Evolution.

Although evolution eliminated most of the Neanderthal genes inherited by modern humans tens of thousands of years ago, a small percentage still remains. Perhaps because they helped early modern humans adapt to the new environment when they left Africa and came to Eurasia.

Neanderthal adaptations have been preserved

According to Lasse Villen Sørensen, senior researcher at the National Museum in Copenhagen, this is an exciting study.

The fact that people are A or B people could be a genetic adaptation that characterizes us to this day, he says.

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About 70,000 years ago, waves of Homo sapiens migrated from Africa to Eurasia.

When they arrived, they encountered Neanderthals, Homo sapiens, who had already adapted to life in a cold climate after settling the region hundreds of thousands of years ago.

Thanks to hybridization between the two groups, humans today have up to four percent Neanderthal DNA, including genes associated with skin and hair pigmentation, fat and immunity.

Some Neanderthal DNA is also associated with sleep, specifically the circadian rhythm.

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It is exposed to varying daylight

When the first humans moved north from Africa, they first experienced varied daylight, with shorter days in winter and longer days in summer. Neanderthals' genes for circadian rhythms likely helped them adapt to the new environment.

When humans evolved in tropical Africa, days were on average 12 hours long. Hunter-gatherers spend only 30% of their waking hours finding food, so 12 hours would be enough. But the further north you go, the shorter the days become in winter, when there is particularly little food. It therefore makes sense that Neanderthals and humans would begin gathering food as soon as it became light.

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– They have adapted to these regions, where the difference between seasons is greater than in Africa. Sorensen says there's something about sunlight that affects the biological clock, so that people do certain things at certain times, which today we call A and B people.

– So when humans have children from ancient species that have adapted to this region with seasonal differences, they pass on mutations to us that make us more adaptable to climate, temperature and daylight, he explains.

In the North, it is useful to have a biological clock that is more able to adapt to changing light levels in the seasons. This ability is what makes people more inclined to wake up early.

Neanderthals were A

In this study, researchers compared DNA from modern humans with genetic material from Neanderthal fossils. It turns out that Neanderthals carried some of the same genetic variants as the humans who claim to be superhumans.

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To find out whether people living today still have these variants, the researchers looked to the UK Biobank. It is a medical database containing health information, including genes, from hundreds of thousands of people, including self-reported data on whether people consider themselves to be people.

Neanderthal genes have always been associated with waking up early.

But take it with a grain of salt…

According to Peter Ka Jensen, a retired physician who has written several books on human evolution, the research is credible.

But as the authors also say, more studies are needed before we can be sure that we actually inherited the A-man genes from Neanderthals, he says.

– Among other things, it will be important to study more people living at different altitudes above sea level. Neanderthals also lived in the lowlands of Western Europe, and many early modern humans lived in East Africa, where the elevation in many places ranges from 1,500 to 2,000 meters above sea level.

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Lacey Felin Sorensen agrees.

– He says more studies of Neanderthals, Denisovans, and ancient Homo sapiens, and a larger population today than just Great Britain, are needed to follow up on this study's interpretations.

Because the researchers only used data from people in the United Kingdom, the findings do not necessarily apply to all modern people.

In addition, there may be many factors other than genetics that affect a person's waking time, including social and environmental influences.

– It is also conceivable that man could be a person without having any relation to primitive man. It is of course an interesting observation, but I am not sure whether it affects our understanding and view of modern people, says Peter K. A. Jensen.

reference:

Kela Velasquez-Arcelay et al: An ancient introduction to the features of the human circadian clock. Genome Biology and Evolution, 2023. doi.org/10.1093/gbe/evad203