Recent studies have shown that Neandertal genes have contributed to human immunity and modern disease. A new study published today in the American Journal of Human Genetics has found that Neandertal genes have contributed to other characteristics, too, including skin tone, hair color, sleep patterns, mood, and even a person's smoking status.
It all started when researchers from the Max Planck Institute for Evolutionary Anthropology wanted to know what the influence Neandertal DNA might be having in people today that were not related to a disease. Using data from the UK Biobank pilot study, which represents more than 112,000 participants, the researchers were able to find these common ordinary traits that were influenced by Neandertal DNA.
"Earlier studies had suggested that human genes involved in skin and hair biology were strongly influenced by Neandertal DNA," says Janet Kelso, Ph.D., the group leader of the study. "But it hadn't been clear how."
In their study, the researchers observed multiple different Neandertal alleles contributing to skin and hair tones. They found that some of the alleles were associated with lighter skin tones and others with darker skin tones. The same was true for hair color.
"These findings suggest that Neandertals might have differed in their hair and skin tones, much as people now do" adds Michael Dannemann, Ph.D., first author of the study.
According to Kelso, the traits influenced by Neandertal DNA are all linked to sunlight exposure. The Neandertals were likely well adapted to lower and more variable levels of ultraviolet radiation from the sun than the humans who arrived much later.
"Skin and hair color, circadian rhythms and mood are all influenced by light exposure," the researchers wrote. "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."
Kelso and her group now plans to explore and learn what other aspects Neandertals may have influences on modern-day traits as more data becomes available.