The evolution of human language is a complex and contentious one. To try and deeply understand its dynamics, scientists implanted a human “language gene” in mice. The outcome? Deep changes to the manner in which these little creatures squeak and chat.
The “Talking” Mice
Mouse babies carrying the human version of the language gene spoke differently to normal mice. They made more advanced, higher-frequency squeaks, indicating a complete overhaul of their communication.
Decoding the Sounds
Baby mice all produce ultrasonic squeaks, which are broken down into four “letters”: S, D, U, and M. Scientists discovered that the engineered mice made differing varieties of variations, indicating a profound linguistic shift.
It’s Not All Squeaks
The genetically altered mice aged while continuing to vary from each other in their calls. Males, for instance, “spoke” more intelligibly when attempting to woo females, being more sophisticated in their calls.
Say Hello to the NOVA1 Gene
The alterations in calling are associated with a gene named NOVA1. This is an important gene when it comes to brain function and communication in many species, ranging from birds to mammals.
The Human Twist
In humans, the NOVA1 gene differs ever so slightly. One amino acid difference, from isoleucine to valine at residue 197, seems to have dramatic effects on abilities of vocal communication.
What Went On in the Brain?
To the surprise of the scientists, the human variant of NOVA1 failed to disrupt brain growth or movement control in mice. It did however alter the way RNA attached to genes that mediate vocalization.
A Surprising Discovery
“How crazy is that? We didn’t think it would work,” said lead researcher Robert B. Darnell. The surprising outcome only lent further support to the theory that genetic alterations could have a dramatic effect on communication.
Did Neanderthals Miss Out?
Surprisingly, the Neanderthals and Denisovans did not carry the same NOVA1 variant found in today’s humans. That would suggest that they did not share the same capacity for complicated speech.
Evolutionary Disadvantage?
The African origin of the human-specific variant would have spread across the world. Might this have provided Homo sapiens with a decisive edge over competing hominin species?
A Key to Our Success?
If it was the complexity of the voice that made the difference and helped humans survive and reproduce, then this gene could be part of the jigsaw in explaining our success in evolution.
More Questions Than Answers
This study uncovers interesting findings, but it raises more questions than answers. How do other genes play a role in speech? What are the environmental influences in human communication evolution?
The Science of Speech—A Never-Ending Mystery
This study, published in Nature Communications, opens up vocal evolution to a new understanding. And yet, the science of speech is a never-ending mystery, with so much still to learn.
