Depression, Addiction Linked to Neanderthal DNA: Study

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Depression and unhealthy habits like smoking are difficult to deal with. A new study suggests that being hooked on these behaviors or routines could be attributed from the DNA one inherited from his Neanderthal heritage.

According to News4SA.com, Neanderthals lived in Europe and Asia 200,000 years ago, before the modern people arrive. The modern people split off on the evolutionary tree hundreds of thousands of years ago. However, the ancestors of modern people interbred with Neanderthals about 50,000 years ago after leaving Africa.

Researchers believed that the modern people were able to retain this Neanderthal DNA because it is helpful in surviving new environments. Asian and European ancestry has around 2 percent of DNA from Neanderthals.

Unfortunately, DNA reported that some of these traits were no longer beneficial to the modern environment. A previous study, published in the American Journal of Human Genetics, revealed that Neanderthal genes were linked to certain immune disorders, allergies and asthma.

On Friday, the researchers announced that certain genes inherited from Neanderthals are also associated with one's psychiatric disorder, blood clotting and addictive behavior. The statement was said after the team studied tens of thousands of modern people's medical records and genetic histories.

"Our main finding is that Neanderthal DNA does influence clinical traits in modern humans," said John Capra, an evolutionary geneticist and assistant professor of biological sciences at Vanderbilt University. "We discovered associations between Neanderthal DNA and a wide range of traits, including immunological, dermatological, neurological, psychiatric and reproductive diseases."

The study was the first to compare Neanderthal DNA in the genomes of a large population of adults to European ancestry. About 28,000 people and their health records show a "subtle but significant impact on modern human biology," Capra said.

Neanderthal genes were linked to a higher risk of nicotine addiction. Many bits of the said genes were associated with psychiatric and neurological effects. Others raise the risk while some others lower it.

"The brain is incredibly complex, so it's reasonable to expect that introducing changes from a different evolutionary path might have negative consequences," said co-author Corinne Simonti, a doctoral student at Vanderbilt.

Other effects were observed in the blood. Per the report, Neanderthal variants led to increased blood coagulation, which is helpful in healing wounds more quickly and keeping pathogens from entering the body. However, people today with thicker blood are at higher risk of several health problems, including stroke, pulmonary embolism and pregnancy complications.

"This study has modern-day clinical relevance because it reveals how evolutionary history has led to some differences in disease risk between populations," Capra told Discovery News.