Carl Zimmer in The New York Times:
Scientists have discovered a glitch in our DNA that may have helped set the minds of our ancestors apart from those of Neanderthals and other extinct relatives. The mutation, which arose in the past few hundred thousand years, spurs the development of more neurons in the part of the brain that we use for our most complex forms of thought, according to a new study published in Science on Thursday.
“What we found is one gene that certainly contributes to making us human,” said Wieland Huttner, a neuroscientist at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, and one of the authors of the study. The human brain allows us to do things that other living species cannot, such as using full-blown language and making complicated plans for the future. For decades, scientists have been comparing the anatomy of our brain to that of other mammals to understand how those sophisticated faculties evolved.