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Itchy eyes once the flowers start blooming each Spring time? For that, you can thank your Neanderthal ancestors, two newly released studies suggest.
Although scientists once thought of Neanderthals as mindless beasts, a growing body of evidence has turned up showing that Neanderthals not only lived sophisticated lives, but also sometimes mated and coexisted with humans. Some studies have shown that as much as 6 percent of modern Eurasian genomes were inherited from ancient hominins, including Neanderthal.
In two studies published in the American Journal of Human Genetics earlier this week, researchers were able to pinpoint three genes from Neanderthals and Denisovans – a type of early human – that may have helped regulate immunity and fight infection. It helped early humans as they traveled the world and encountered new types of bacteria, fungi and parasites.
“When the body detects that there is some foreign substance in the body, these are the guys that react immediately,” Janet Kelso, a scientist from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany , who led research for one of the studies, told NPR. “It kind of calls in the big guns.”
However, those same disease-fighting systems can also overreact to certain substances, like pollen or animal hair, thereby increasing one’s risk of allergies. It remained unclear whether those genes are still useful in preventing people from succumbing to dangerous pathogens, scientists said, or whether they’re just a nuisance today.
“That’s sort of the $1 million question,” Lluis Qutintana-Murci, with the Pasteur Institute in Paris, who led the second research team, told NPR. “What was good in the past may or may not be good for us today.”
Scientists said the recent findings reflected just one among the many ways our genes have been influenced by Neanderthals. Past studies have found that Neanderthal DNA has also influenced human hair and skin. The latest research seemed to indicate that interbreeding served a functional purpose, Kelso said.
“Neanderthals, for example, had lived in Europe and western Asia for around 200,000 years before the arrival of modern humans,” she said in a statement about the study. “They were likely well adapted to the local climate, foods and pathogens. By interbreeding with these archaic humans, we modern humans gained these advantageous adaptations.”