Having Neanderthal DNA in your genes significantly increases the risk for depression, nicotine addiction, stroke, pregnancy complications and many other health problems, finds a new survey.
The study, published in the journal Science, provides a living reminder that no human today is a "purebred," since early Homo sapiens interbred with different species in Africa, Asia and Europe. Less is known about what happened in Africa, but sequencing of the Neanderthal genome has made it possible to link Neanderthal DNA to aspects of appearance and the health risks of today's Europeans and Asians.
"This study has modern-day clinical relevance, because it reveals how evolutionary history has led to some differences in disease risk between populations," senior author John Anthony "Tony" Capra told Discovery News.
Photos: Are You Related to Neanderthals?
"In terms of treating these diseases, it will be important to understand how these bits of Neanderthal DNA exert their influence at the molecular level."
Capra, an evolutionary geneticist and assistant professor of biological sciences at Vanderbilt University, and his colleagues analyzed a database containing the anonymous health records of 28,000 U.S. patients. The scientists next looked at the genomes of each person, focusing on their Neanderthal DNA, and then compared the two sets of data to see how the DNA had influenced the patients' risks for the different health problems.
A finding is "that having Neanderthal DNA at one location in the genome significantly increased risk for blood hyper-coagulation," Capra said. Back in the day, this trait might have helped early humans to seal wounds more quickly, preventing infections, but now it can increase the risk for stroke, blood clots and pregnancy complications.
Ancient Human With 10 Percent Neanderthal Genes Found
Neanderthal DNA also appears to affect skin and hair color, freckles, and even warts and calluses.
"We also found several surprising associations between Neanderthal DNA and psychiatric and neurological phenotypes (resulting behaviors) like depression and nicotine addiction," Capra said.
He quickly added that Neanderthals did not even have tobacco, which is native to the Americas. They probably were not depressed, either.