In a lab at Rockefeller University in New York, a mouse squeaks. But this is no ordinary squeak. It is a strange, complex sound, unlike anything heard from a mouse before. The difference lies in a single gene — a gene that may hold the key to one of humanity’s most defining traits: the ability to speak.

A gene variant present in most people might have contributed to cognitive differences between humans and their closest relatives.

A new study has revealed that a single genetic mutation, found in all modern humans but absent in Neanderthals and Denisovans, could have played a role in the evolution of speech and language. The research,