Are you busy pumping yourself with Zyrtec? Are you are looking for someone or something to blame for allergies this season? Look no further. Your Neanderthal DNA could be the reason.
According to recent studies, about 2 percent of the DNA in most living people today came from trysts between ancient humans and their Neanderthal neighbors thousands and thousands of years ago. So now, scientists are trying to figure out what (if any) effect that Neanderthal genetic legacy has on our lives today.
A pair of papers were published in the American Journal of Human Genetics this week, and two research teams reported that in several people, a group of genes that control the first line of defense against pathogens was likely inherited from Neanderthals.
These are the same genes that seem to play a role in people’s allergic reaction to things such as pet fur and pollen, the researchers reported.
“It’s a bit speculative, but perhaps this is some kind of trade-off,” said a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany and lead author of one of the new studies, Janet Kelso. “Increased resistance to bacterial infection was advantageous, but may have resulted in some increased sensitivity to non-pathogenic allergens.”
Scientists think that roughly 50,000 years ago, humans who left Africa came across Neanderthal settlements in the Middle East. And on some occasions, those interactions led to couplings that left a mark on the genomes of people with ancestors from Asia and Europe.
So not everyone with Neanderthal DNA inherited the same genes. However, the immunity genes seem to be more popular than other genes, LA Times reports.
The researchers found that in some European and Asian populations, these Neanderthal genes can be found in 50 percent of humans.
“That’s huge,” said the senior author of the other study and evolutionary geneticist at the Pasteur Institute in Paris, Lluis Quintana-Murci. “It came as a big surprise to us.”
These findings imply that these Neanderthal genes must have been good for our ancestors if they are still sticking around today, particularly so prominently, said Peter Parham, a Stanford School of Medicine professor of immunology and microbiology not involved in the research. If the DNA weren’t necessary, it would not still be in our gene pool.
“It suggests that there was a benefit for the migrating modern human and the archaic human to get together,” Parham said. “What has survived is a hybridization of those populations.”
Both research groups reported on a cluster of three genes known collectively as TLR6-TLR1-TLR10. These make up part of the body’s innate immune response to invading viruses and bacteria, The Times reports.
The results of the studies will be added to a group of work that sheds some light on the importance of our Neanderthal relatives. “We’re right in the beginning,” Parham said. “This type of work has really lit a fire beneath archaeologists to try to find more and more samples of Neanderthals so geneticists can do more population studies.”