Neandertals have long since walked on Earth; however, about 2 percent of their DNA remains in non-African people living today. Now, researchers have discovered those Neandertal genes have contributed a lot more than just to human immunity and modern diseases.
In a new study, researchers have found our Neandertal inheritance also contributes to other characteristics including skin tone, hair color, sleep patterns, mood, and even whether a person smokes.
Janet Kelso, from the Max Planck Institute for Evolutionary Anthropology in Germany, and her team became interested in connections between Neandertal DNA and characteristics after an earlier study found associations between Neandertal DNA and disease risk.
For the study to be valid, the researchers needed data representing a large number of people, and because Neandertal alleles are somewhat rare, they turned to a previous UK Biobank pilot study.
The data in the Biobank pilot study represented more than 112,000 participants, which included genetic information and information on many traits related to physical appearance, diet, sun exposure, behavior, and disease.
The researchers found that there were multiple different Neandertal alleles that contributed to skin and hair tones. What was surprising is that they discovered that some Neandertal alleles were found in association with lighter skin tones and others with darker skin tones; the same was reviled for hair color.
“We can now show that it is skin tone, and the ease with which one tans, as well as hair color, that are affected,” Kelso said.
Michael Dannemann, first author of the study, added:
“These findings suggest that Neandertals might have differed in their hair and skin tones, much as people now do.”
Additionally, it was found that Neandertal DNA also influenced behaviors like mood, smoking, and sleep patterns. For instance, people with specific Neandertal variants tended to be smokers, while other variants were found more frequently in “night people.”
Many of the traits influenced by Neandertal DNA, which includes skin and hair pigmentation, mood, and sleeping patterns, are all linked to sunlight exposure.
Neandertals had already lived in Eurasia for thousands of years before the arrival of modern humans about 100,000 years ago. Compared to the new human arrivals from Africa, Neandertals would have been well adjusted to lower and inconstant levels of ultraviolet radiation from the sun, the researchers wrote:
“Skin and hair color, circadian rhythms, and mood are all influenced by light exposure.
“We speculate that their identification in our analysis suggests that sun exposure may have shaped Neandertal phenotypes, and that gene flow into modern humans continues to contribute to variation in these traits today.”
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