You may blame your depression and addictions on your parents but the actual cause might be ancestors dating back a few more generations (actually, a LOT more). New research suggests that modern afflictions such as depression, nicotine addiction, urinary tract disorders and others may be due to DNA passed down from one of your – brace yourself – Neanderthal ancestors.
This shocking news was revealed by evolutionary geneticist Tony Capra at the 2016 AAAS Annual Meeting held this week in Washington D.C. and in a study in the journal Science. He was part of a team looking for potential affects of Neanderthal DNA on current human biology. It’s known that humans of Eurasian descent have received 1 to 4 percent of their DNA from Neanderthals.
The researchers used a database that connected biological samples from 28,000 people to their health records. They looked for instances of specific conditions and traits – like heart disease and depression – and then checked to see if affected individuals had Neanderthal DNA. The results were surprising, said Capra.
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.
The influence wasn’t necessarily good. They found that Neanderthal DNA increased the risk of developing keratosis – skin lesions from sun exposure. It increased blood coagulation, which heightens the chances of strokes and heart attacks due to blood clots.
The big surprise was that Neanderthal DNA increased the risk of becoming addicted to nicotine, a New World substance not known to Neanderthals. It affected people with depression – both negatively and positively – and was found consistently in those with psychiatric and neurological issues, says Vanderbilt doctoral student and study author Corinne Simonti.
The brain is incredibly complex, so it's reasonable to expect that introducing changes from a different evolutionary path might have negative consequences.
Some of these Neanderthal traits may have once been beneficial - fast blood coagulation would help wounds heal quickly – but they’re causing plenty of problems in modern humans. However, Simonti warns that before we try to get rid of them, we might want to figure out why we’ve held on to them for so long.
… just because a Neanderthal variant negatively affects or increases your risk for a disease today doesn’t mean it’s not protective in some other way, and also there could be certain protective effects that we just haven’t been able to detect.
For the time being, blame all of your problems on the Neanderthals.