A study published in the American Journal of Human Genetics found that Neanderthals may be the species to thank for our exemplary immune system.
When modern humans left Africa for Europe and Western Asia, they encountered archaic species like Neanderthals and Denisovans, who were probably well-adapted to the environment and pathogens. Upon interbreeding, modern humans acquired beneficial mutations from these species, thus increasing their odds for survival.
The fact that these haplotypes (set of DNA variations) have stuck around for thousands of years likely means that they convey some evolutionary advantage in our ability to survive and reproduce.
Researchers found that the inherited variations lead to increased gene expression in white blood cells – the soldiers of your immune system. This leads to decreased prevalence of Helicobacter pylori (linked to ulcers and stomach cancer), yet a greater susceptibility to allergies.
This finding is just a piece of the puzzle in our evolutionary history and may explain why modern humans were the only human-like species to survive.