How did the human brain evolve?
New work suggests a prominent role for genes in the SRGAP2 family, as explained here. Data suggest a mechanism where incomplete duplication - most likely at SRGAP2C - created a novel gene function some 2–3 mya, which is a time corresponding to the transition from Australopithecus to Homo and the beginning of neocortex expansion. Further, in the mouse neocortex, Srgap2 promotes spine maturation and limits spine density, supporting sustained radial migration and leading to the emergence of human-specific features.