In a discovery that rewrites our understanding of when human language evolved, researchers at the University of Iowa have identified tiny genetic regions shared with Neanderthals that may hold the biological blueprint for how we speak and communicate. These regions, called HAQERs (Human Ancestor Quickly Evolved Regions), comprise less than one-tenth of a percent of our genome—yet they exert roughly 200 times more influence on language ability than any other genetic region, according to a study published in Science Advances.
The finding matters because it pushes the origins of language-related biology much further back in evolutionary time than scientists previously thought. Language is one of the defining characteristics of modern humans. While many animals communicate, humans possess an exceptional ability to create, adapt, and expand language in ways unmatched by other species. The discovery suggests that the fundamental biological hardware for sophisticated communication existed long before modern humans emerged as a distinct species.
Jacob Michaelson, PhD, Roy J. Carver Professor of Psychiatry and Neuroscience at the University of Iowa Roy J. and Lucille A. Carver College of Medicine, led the research team alongside first author Lucas Casten, PhD, now a postdoctoral researcher at the Max Planck Institute of Psychiatry in Munich, Germany. The team traced genetic influences across approximately 65 million years of evolutionary history using an innovative tool called an evolutionary-stratified polygenic score, which separates genetic effects according to when they emerged during evolution.
The research built on work that began decades earlier. In the 1990s, Bruce Tomblin, PhD, now professor emeritus in the UI Department of Communication Sciences and Disorders, studied the language abilities of 350 Iowa students, carefully documenting their skills and collecting DNA samples. Years later, when Michaelson's laboratory completed genetic sequencing through NIH-funded research, scientists could examine how differences in DNA correlated with variations in language ability. This unusual window into individual differences in language abilities revealed the outsized power of HAQERs.
Think of HAQERs as volume knobs on genes—regulatory regions that control how loudly or quietly genetic instructions are expressed. The FOXP2 gene, identified more than 20 years ago, works as the hand that turns these knobs. Together, they orchestrate the biological "hardware" of language, while speech and writing themselves function as the "software."
The most striking finding emerged when researchers looked backward through time. The analysis revealed that these genetic "volume knobs" were already present in Neanderthals and may have been even slightly more pronounced than in modern humans. This suggests HAQERs are ancient biological innovations linked to language—which is especially significant given that Neanderthals differed substantially from modern humans in many aspects of cognition. Archaeological evidence already shows Neanderthals had culture, social organization, and complex behaviors. Combined with the new genetic findings, this strongly suggests that some form of sophisticated communication existed long before modern humans appeared.
Yet the research also posed a puzzle: if HAQERs are so beneficial for language, why did they stop changing rather than continuing to evolve? The answer likely involves balancing selection. These genetic regions support fetal brain development in ways that also increase brain and skull size. Before modern medicine, there were strict biological limits to how large an infant's head could become without making childbirth dangerously difficult for both mother and child. That ancient constraint may have locked HAQERs in place, even as other cognitive abilities continued to evolve. We carry in our genome not just the machinery of language, but the evolutionary history of survival itself.