A newly published study suggests that a tiny fraction of human DNA plays an outsized role in language ability. Researchers at the University of Iowa found these genetic regions were present before modern humans and Neanderthals diverged. The findings push back the timeline for the biological basis of language.
The study, published in Science Advances, focused on Human Ancestor Quickly Evolved Regions, or HAQERs. These regulatory DNA segments act like volume controls for genes involved in brain development. They make up less than 0.1 percent of the genome yet exert roughly 200 times more influence on language skills than other regions.
Jacob Michaelson, a professor at the University of Iowa, led the research. He noted that the sequences were already present in Neanderthals and may have been slightly more pronounced than in modern humans. "We can say humans at least had the 'hardware' for language earlier than what we previously thought," Michaelson said.
The team traced the genetic effects across 65 million years of evolution using data originally collected in the 1990s. Bruce Tomblin had studied language skills in Iowa students and preserved DNA samples for later analysis. The work also points to an evolutionary tradeoff, where further expansion of these regions may have been limited by risks during childbirth.