Back in 2010, scientists discovered that Eurasians contain approximately 1 to 4 percent of Neanderthal DNA in their body, leading many to hypothesize about the effects of these genetic inheritances on human behavior. Now, a new study by researchers from Vanderbilt University confirms that adults of European ancestry possess Neanderthal genetics that have a subtle influence on modern human biology.
"Our main finding is that Neanderthal DNA does influence clinical traits in modern humans: We discovered associations between Neanderthal DNA and a wide range of traits, including immunological, dermatological, neurological, psychiatric and reproductive diseases," John Capra, senior author of the paper, said in a press release.
The team revealed that Neanderthal DNA variants influence the skin biology of modern humans, including the risk of developing skin lesions, as well as increase the risk of nicotine addiction. Other variants revealed relationships to depression, some with positive influences and others with negative influences.
"The brain is incredibly complex, so it's reasonable to expect that introducing changes from a different evolutionary path might have negative consequences," said Corinne Simonti, first author of the study.
The pattern of genetic associations found in the research suggest that the modern human population contains Neanderthal DNA that was likely advantageous 40,000 years ago during the migration into non-African environments, which contained different kinds of pathogens and levels of sun exposure.
Despite some benefits, the team believes that many of these adaptations are no longer advantageous. For example, one Neanderthal variant increases blood coagulation, which probably evolved to help our ancestors cope with new pathogens and seal wounds quicker to prevent their entrance into the body. However, in modern environments this is detrimental due to the fact that hypercoagulation increases the risk of stroke, pulmonary embolism and complications during pregnancy.
The findings are available online ahead of their Feb. 12 release in Science.
