Modern humans who arrived in Eurasia some 70,000 years ago inherited from the Neanderthals with whom they lived until their disappearance not only infectious viruses, but also the genetic tools to combat them, according to research published today in the journal Cell.
In fact, Many Europeans and Asians nowadays hold around 2% of Neanderthal DNA in their genomes.
Modern humans who left Africa and arrived in Eurasia met there with Neanderthals who had adapted to that geographical area for hundreds of thousands of years.
According to David Enard, one of the authors of the research and assistant professor of ecology and evolutionary biology at the University of Arizona (USA), "it is not an exaggeration to imagine that, when modern humans met Neandertals, they became infected with pathogens that came from their respective environments"
But those Neandertals also transmitted to modern humans "genetic adaptations to address some of those pathogens."
"It made much more sense to modern humans simply borrowing the genetic defenses already adapted from the Neandertals to wait to develop their own adaptive mutations, something that would have cost much more time, "said Enard in the article that collects the findings of the research.
Enard, Dmitri Petrov, evolutionary biologist at the School of Humanities and Sciences at Stanford University (USA), and the other researchers compiled a list of more than 4,500 genes of modern humans known to interact in some way with the viruses.
"We focus on these genes because those that interact with viruses are much more likely to have been involved in adapting against infectious diseases compared to those that have nothing to do with viruses," Enard argued.
They then compared their list with a DNA database of the Neanderthal man and discovered that 152 fragments of those more than 4,500 genes of modern humans were also present in the Neandertals.
In modern humans, these 152 gene fragments interact with RNA-like viruses such as AIDS (HIV), influenza A, and hepatitis C.
This research, in addition to revealing new details about human evolution, can help to find evidence about the outbreaks of ancient diseases, even when the responsible viruses no longer exist, according to their authors.