10 unexpected ways Neanderthal DNA affects our health

As far back as 250,000 years ago, the ancestors of most modern people in Europe and Asia left Africa and journeyed toward the colder northern terrain of Eurasia. There, they encountered our closest, now-extinct human relatives — the Neanderthals. Over thousands of years, these groups mated and exchanged DNA. 

Today, we can still see the genetic legacy of these interbreeding events: approximately 2% of the genomes of people outside of Africa comes from Neanderthals. 

Thanks to fossil discoveries and advances in genome-sequencing technologies, scientists have made a plethora of discoveries about the DNA we inherited from our long-dead cousins and how it may impact our Health. 

Here are 10 ways that Neanderthal DNA may contribute to particular diseases and physical traits in modern humans. 

Related: Neanderthal woman's face brought to life in stunning reconstruction

1. Allergy risk

In 2016, scientists discovered Neanderthal genes in some modern humans that encode proteins that stimulate the immune systems' response to pathogens, and that these genes may also predispose people to allergic diseases. 

Modern humans inherited gene variants from Neanderthals in a family of proteins called Toll-like receptors (TLR). TLRs are found on the surface of cells and play an important role in innate immunity — the body's first line of defense against pathogens. TLRs bind to invading microbes and stimulate the immune system to respond.