Your Body Fights Sickness Like a Caveman — And That's a Good Thing


Thousands of years ago, modern humans met Neanderthals in Europe at whatever the equivalent of a singles bar was. They started having a bunch of sex, and now we exist. In the throes of creating the future of humanity, Neanderthals gave us two things: their kickass, pterodactyl-fighting immune systems and allergies.


Those are the discoveries of two papers published Thursday from researchers at the Max Planck Institute for Evolutionary Anthropology, the Institut Pasteur and the National Center for Scientific Research in Paris.

We've already heard that 1% to 6% of modern Eurasian genomes came from two forms of early man, the Neanderthals and the Denisovans. But the new studies explore how our inherited traits affected genes, specifically Toll-like receptors, which detect and respond to things like bacteria, fungi and parasites.

"We found that interbreeding with archaic humans — the Neanderthals and Denisovans — has influenced the genetic diversity in present-day genomes at three innate immunity genes belonging to the human Toll-like-receptor family," said Janet Kelso of the Max Planck Institute, according to Science Daily.

Lluis Quintana-Murci, one of the paper authors from the Institut Pasteur and the CNRS, used data from the 1,000 Genomes Project along with those taken from extremely old hominins, the group of all things considered remotely human (not to be confused with hominids, which also includes apes). His team looked into how certain genes act in the innate immune system, which keeps the body protected from infections.

"These, and other, innate immunity genes present higher levels of Neanderthal ancestry than the remainder of the coding genome," Quintana-Murci said, according to Science Daily. "This highlights how important introgression events [the movement of genes across species] may have been in the evolution of the innate immunity system in humans."


From what both studies found, the timing for when our bodies became better at protecting themselves and when modern man would've started mating with the ancient hominins checked out. According to the Planck Institute report, our protein-coding genes adapted somewhere between 6,000 to 13,000 years ago, around when humans figured out how to farm and progressed beyond hunting and gathering.

Your body is mighty because of all that. But it also meant that you gained allergies, since, when the Neanderthals and Denisovans came into the picture, they brought with them traits their bodies had adapted to over hundreds if not thousands of years — things like metabolism, diet and weather. According to Kelso, that's probably where our allergies came from.

"What has emerged from our study as well as from other work on introgression is that interbreeding with archaic humans does indeed have functional implications for modern humans," Kelso said, according to Science Daily, "and that the most obvious consequences have been in shaping our adaptation to our environment — improving how we resist pathogens and metabolize novel foods."

So next time your seasonal allergies act up, just remember this: You're part caveman. And it's a small price to pay to not die off like the humans of thousands of years ago.


h/t Science Daily