DNA from Ancient Bones Reveals How Indigenous Americans Got Their Mucus

Mucus does more than simply rocket out of our noses when we sneeze. The sticky, viscous secretion that coats many organs also forms our innate immune system’s first line of defense, helping trap harmful pathogens. Now, scientists have tracked the winding evolutionary path this variant took from its origins in Denisovans—a mysterious ancient human ancestor—to our close cousins the Neanderthals and finally modern humans. David Peede, a recipient of the 2025 Blavatnik Family Graduate Fellowship in Biology and Medicine at Brown University, is one of the authors of a published paper in the journal Science, which sheds light on how a critical gene moved between different species or subspecies and the evolutionary forces that might have driven its spread.