Science reports:

When early farmers of the Vinca culture first sowed barley and wheat 7700 years ago in the rich soil of the Danube River and its tributaries, they changed more than their diet: They introduced a new way of life to the region. They crowded together in mud huts, living cheek by rump with aurochs, cows, pigs, and goats—and their poop—in settlements that eventually swelled to thousands of people. Togetherness brought a surge in diseases such as influenza, tuberculosis, and other maladies spread from animals to people and through early farming communities.

Now a new study of ancient DNA shows how the immune systems of those early farmers responded to this new, pathogen-ridden environment. The Neolithic Revolution was a “turning point” in the evolution of immune responses to infectious disease, according to a paper published today in eLife. The study suggests that in Europeans, evolution favored genes that throttled back inflammatory reactions to pathogens like influenza, restraining the hyperalert inflammatory response that can be deadlier than the pathogen itself.

“This study does a great job of showing that our immune system has continued to evolve in response to pathogen pressure,” says population geneticist Joseph Lachance of the Georgia Institute of Technology. But he notes that the paper relies on an unproven method of predicting ancient immune responses. “I buy it, but it needs to be studied [more] when we have more ancient DNA.”

Researchers have long suspected that early farmers got sick more often than nomadic hunter-gatherers. Studies suggest farmers in large Neolithic sites such as Çatalhöyük in Turkey faced a flurry of new zoonotic diseases such as influenza and salmonella, as well as new animal-borne strains of diseases like malaria and tuberculosis. “If farmers got sick more, how did their immune systems change?” asked infectious disease specialist Mihai Netea of Radboud University Nijmegen Medical Centre, who led the study. [Continue reading…]