How a single gene alteration may have separated modern humans from predecessors

Scientists at the University of California San Diego have pinpointed a single gene difference that could help explain why modern humans have distinct cognitive abilities compared to Neanderthals and Denisovans. By using stem cells and gene editing, researchers recreated a Neanderthal-like version of the NOVA1 gene in human brain organoids—miniature, lab-grown models of the brain.

This gene, NOVA1, acts as a key regulator influencing many others during early brain formation. When modified to carry the Neanderthal variant, the organoids developed with noticeable differences: they were shaped differently, their cells multiplied uniquely, their synaptic connections formed in alternate ways, and their electrical activity failed to synchronize like those in typical human brain organoids.

These findings provide a new window into human evolution, showing how a single genetic change can have major impacts on brain development and potentially contribute to uniquely human traits such as complex social behaviors, creativity, and advanced language

The research opens a new field that combines stem cell science, neuroscience, and ancient DNA—enabling scientists to test how dozens of other genetic differences might have contributed to what makes us human. The project directors are planning further studies to explore additional genes that separate our species from extinct relatives