Modern Humans Retain Neanderthal Genes That Once Helped Fight Ancient Viruses
Diseases have been major drivers of human evolution. Now, a study in the journal Cell suggests Neanderthal genes that are retained in modern humans once helped fight ancient viruses.
Modern humans and Neanderthals interbred at least twice, around 100,000 and 50,000 years ago.
When they met, each carried viruses against which the other lacked protection. But their hybrid children retained the "antidote" genes and passed them on.
People of European and East Asian descent still retain some of those genes within the 2-3 percent of their genomes that is Neanderthal in origin.
"We are actually able to tell which kinds of viruses were exchanged between Neanderthals and modern humans," said lead author David Enard, assistant professor of ecology and evolutionary biology at University of Arizona.
Enard compared these traces to fossilized footprints that have not yet eroded away.
"Because they were advantageous, they rose in frequency pretty fast in our modern human ancestors, but, because they rose to high frequencies, now it takes time for these stretches of Neanderthal DNA to disappear."
He also emphasized that these genes offer no modern protections, and that vaccines are still the only way to protect against viruses.