The Neanderthals were a prehistoric species of humans that existed from about 400,000 years ago to about 40,000 years ago. They lived in Europe and Asia and, as a result, encountered modern-day humans as they migrated out of Africa about 55,000 years ago. In the past, scientists have wondered whether conflict with modern-day humans, also known as Homo sapiens, is what led to the extinction of Neanderthals. However, some theorize that Homo Sapiens may have absorbed them into their population by interbreeding with them. Whatever the reason for their extinction, interbreeding still occurred between the two species. And now, some living humans have genomes that are filled with the genetic evidence.
Who Has Neanderthal DNA?
Because of the fact that Homo Sapiens only encountered Neanderthals outside of Africa, the percent of Neanderthal DNA in modern humans from African populations is virtually zero. However, European and Asian people have genomes that are made of about one to two percent Neanderthal DNA. The impact of Neanderthal DNA, is, therefore, dependent on an individual’s ancestry.
How Does This DNA Affect Humans Today?
Those who do have Neanderthal DNA in their genomes may be significantly impacted. For example, scientists believe that versions of certain genes that Neanderthals introduced into the genomes of Homo Sapiens contribute to an increased risk of sunburn for living humans. This could be because some of the Neanderthal DNA affects keratinocytes, which are cells that protect against UV radiation. Despite the modern-day inconvenience of sunburns, variations that Neanderthal DNA provided probably allowed prehistoric Homo Sapiens to synthesize vitamin D in spite of the decreased levels of sun exposure in Eurasia.
Genetic variants of Neanderthal origin may have also contributed to the modern-day risk of strokes. This is because a particular variant increases blood clotting. The variant could have been beneficial to prehistoric Homo Sapiens by allowing wounds to close faster and, as a result, protecting against new disease-causing microbes. There is even evidence to suggest that variants introduced through prehistoric interbreeding may contribute to skin color, bone density, and menopause age. With its influence on the traits of living humans, it appears as though Neanderthal DNA managed to leave its mark on modern-day society before it even began.
