Lead Exposure and Human Brain Evolution: A 2-Million-Year Perspective This study reveals that lead exposure was pervasive throughout human evolution, not just a modern phenomenon. Researchers analyzed 51 fossil teeth from multiple hominid species spanning 2+ million years across three continents, finding lead exposure evidence in 73% of specimens using advanced laser ablation mass spectrometry. The team then used human brain organoids carrying either modern or archaic (Neanderthal-like) variants of the NOVA1 gene to test lead's neurological impacts. They discovered that the archaic variant showed greater vulnerability to lead-induced disruption of FOXP2 expression—a gene crucial for speech and language development. This suggests environmental lead exposure may have created evolutionary pressure favoring the modern human NOVA1 variant, potentially giving our species advantages in communication and social cohesion. The research challenges established paradigms about both environmental toxin history and human evolution, proposing that gene-environment interactions with neurotoxins helped shape our species' cognitive development over millions of years.