Neanderthals and allergies: A new genetic study has revealed that the genes inherited by modern humans from Neanderthals after our species interbred 50,000 years ago play a key role in our modern immune system

While these genetic variations have increased the ability of those who have them to ward off infection, they have also left large numbers of people more prone to allergies. Between 1% and 6% of the DNA carried by people from Europe, and much of Asia, has been inherited from Neanderthals or their ancient early human cousins the Denisovans. Indeed, people in East Asia carry up to 15% to 30% more of this prehistoric early human DNA than Europeans. Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now identified three distinct genetic variations from Neanderthals that play a role in allergies. These genes produce proteins known as Toll-like receptors, which are an important part of the innate immune system that provides the first line of defence against infections. However, faults in this immune response also lead to allergies as immune cells react to non-harmful substances such as pollen, food, dust or animal hair. The researchers said that three Neanderthals genes which produce proteins called TLR 6, TLR1 and TLR10 all seem to be associated with, and increase, allergic disease in large numbers of people.