A groundbreaking study has revealed new genetic evidence that could unlock the mystery of why humans developed the ability to speak.
In a recent study published in Nature Communications, researchers from Rockefeller University pinpointed a gene variant that could play a key role in the evolution of human language. This gene, called NOVA1, produces a protein critical for brain development, and its unique version in humans may have helped shape our ability to speak.
"This gene is part of a sweeping evolutionary change in early modern humans and hints at potential ancient origins of spoken language," Dr. Robert Darnell, an author of the study, said in a statement. "NOVA1 may be a bona fide human 'language gene,' though certainly it's only one of many human-specific genetic changes."
While human ancestors like Neanderthals and Denisovans had the anatomical structures needed for speech, only modern humans developed the brain regions crucial for language comprehension and production. The Rockefeller researchers discovered a unique version of the NOVA1 gene found only in humans, which seems to affect vocalization patterns.
In experiments with mice, this human-specific gene variant altered their vocal calls, hinting that NOVA1 may have influenced early human communication.
Using CRISPR gene-editing techniques, researchers inserted the human-specific variant of NOVA1 into mice, replacing the protein normally found in their brains. The results were fascinating: while the variant had no apparent impact on general neural development or motor control, it significantly affected the vocalizations of the mice.
"All baby mice make ultrasonic squeaks to their moms, and language researchers categorize the varying squeaks as four 'letters' — S, D, U, and M," Darnell explained. "We found that when we 'transliterated' the squeaks made by mice with the human-specific I197V variant, they were different from those of the wild-type mice. Some of the 'letters' had changed."
Similar patterns emerged when they studied the hopeful mating calls of male adult mice exposed to female adult mice.
"They 'talked' differently to the female mice," said Darnell. "One can imagine how such changes in vocalization could have a profound impact on evolution."
Researchers say the changes in vocalization patterns suggested that NOVA1 might have had a profound influence on the evolution of communication, even in early humans.
To better understand the evolution of this gene, the team turned to our closest extinct relatives, Neanderthals and Denisovans. They discovered that the human-specific variant of the NOVA1 gene is absent in these archaic humans, reinforcing the idea that this genetic change emerged after our ancestors diverged from them around 250,000 to 300,000 years ago. In contrast, both Neanderthals and Denisovans possessed the same NOVA1 protein found in non-human animals, further supporting the timeline of this genetic evolution.
Further analysis of over 650,000 human genomes revealed that the NOVA1 variant is present in nearly all modern humans. This suggests that the gene may have provided a significant evolutionary advantage, likely linked to vocal communication, and became widespread as humans migrated out of Africa.
The findings are part of a larger effort to understand how genetic changes contributed to the rise of spoken language in humans. NOVA1 is now being studied for its potential connections to language disorders, autism and neurodegenerative diseases, offering new insights into both human evolution and health.
"We believe that understanding these issues will provide important insights into how the brain operates during vocal communications—and how its misregulation leads to certain disorders," first author Yoko Tajima, a postdoctoral associate in Darnell's lab, said in a statement.