Scientists at the University of Iowa Health Care have found tiny genetic "switches" that are very important for human language. These switches developed before humans and Neanderthals became separate species.
Jacob Michaelson, a professor of psychiatry and neuroscience, led the study. He explains that language is what makes humans unique. His team wanted to understand how special genetic parts, called Human Ancestor Quickly Evolved Regions (HAQERs), helped language develop.
HAQERs make up less than 0.1% of our genetic code. Yet, they have about 200 times more impact on language ability than other genetic areas. Michaelson says these regions help build the brain's structure, like the "hardware," while language is the "software."
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Start Your News DetoxHow Ancient Genes Affect Language
The study, published in Science Advances, used research from the 1990s. Bruce Tomblin studied 350 students, recording their language skills and collecting DNA. Michaelson's lab later used these samples to see how genetic differences relate to language.
Michaelson explains that HAQERs are not genes themselves. Instead, they are "regulatory regions that act like the volume knob on genes." He connects this to the FOXP2 gene, which is known to be involved in language. HAQERs are like the "hands" that turn the FOXP2 "volume knob."
To learn more, the researchers used a method called evolutionary-stratified polygenic score (ES-PGS). This allowed them to look at genetic changes over 65 million years.
Neanderthals and Evolutionary Limits
The study found that these genetic "volume knobs" were also in Neanderthals. They might have been even more active in Neanderthals than in modern humans. This means HAQERs are ancient features that helped with language, even if Neanderthals had different overall thinking abilities.
Michaelson noted that HAQERs have stayed fairly constant. Other genes linked to intelligence continued to evolve. This suggests humans had the basic "hardware" for language earlier than thought. This idea fits with archaeological findings that Neanderthals had culture and organized societies, possibly using complex communication.
If HAQERs are so important, why did they stop evolving? The researchers believe it's due to a balance in evolution. HAQERs help with fetal brain development, which also increases brain and skull size. In ancient times, a larger head size made childbirth much more dangerous for both mother and baby.
Michaelson explained that early humans reached a limit in developing brains for language. They couldn't improve this pathway further without increasing childbirth risks. Other genes that boost intelligence but don't affect fetal brain size continued to evolve.
Looking Ahead
Michaelson's team will continue their research with the same participants, who now have families. This will help them understand how language ability is passed down.
They want to separate how much language development comes from genetics versus the environment. Michaelson noted that children in language-rich homes often have better language skills. By studying families, they hope to understand both direct genetic effects and "genetic nurture," where parents' genes shape their children's environment.
The team also plans to use advanced statistics to pinpoint environmental factors in language development. This could lead to important practical uses.
Deep Dive & References
Ancient regulatory evolution shapes individual language abilities in present-day humans - Science Advances, 2026
