SRGAP2 is a gene involved in neuronal migration. A shortened version of this protein allows neurons to migrate faster.
This gene is one of the 23 genes that is duplicated in humans but not in other primates.
This protein has been duplicated twice in the human genome in the past 3.4 million years, once 3.4 million years ago and once 2.4 mya. The 2.4 mya duplication resulted in a shortened version that 100% of humans possess. This shortened version allows faster migration of neurons by interfering with filopodia production. Researchers speculate that this may allow humans to build a thicker cerebral cortex.
The study was reported by Megan Dennis on October 13, 2011 at the International Congress of Human Genetics.