Scientists say they've identified a crucial gene, unique to humans, that may help explain how we learned to use tools and language.
The University of Edinburgh team says it's the first time that a new gene - carried only by humans and not by apes - has been shown to have a specific function within the human body.
The researchers compared the human genome to 11 other species of mammals, including chimpanzees, gorillas, mouse and rat, to find the differences between them.
And the results showed that the gene - miR-941 - is unique to humans, and emerged between six and one million years ago, after humans had evolved from apes.
The gene is highly active in two areas of the brain that control our decision making and language abilities, implying that it could have a role in the advanced brain functions that make us human.
Most differences between species occur as a result of changes to existing genes, or the duplication and deletion of genes. But this one, it seems, emerged fully functional out of non-coding genetic material, previously termed 'junk DNA', in a surprisingly short time.
"As a species, humans are wonderfully inventive - we are socially and technologically evolving all the time. But this research shows that we are innovating at a genetic level too," says Dr Martin Taylor of the university's Institute of Genetics and Molecular Medicine.
"This new molecule sprang from nowhere at a time when our species was undergoing dramatic changes: living longer, walking upright, learning how to use tools and how to communicate. We're now hopeful that we will find more new genes that help show what makes us human."