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

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 new contender for a human 'language gene' can change the way that mice squeak when it is incorporated into their DNA.