Ever since researchers first got a good look at a Neanderthal skull in the 1860s, they were struck by its strange shape: stretched from front to back like a football rather than round like a basketball, as in living people. But why our heads and those of our ice age cousins looked different remained a mystery. Now, researchers have found an ingenious way to identify genes that help explain the contrast. By analyzing traces of Neanderthal DNA that linger in Europeans from their ancestors' trysts, researchers have identified two Neanderthal gene variants linked to slightly less globular head shape in...
