Thumbnail: Primate skulls provided courtesy of the Museum of Comparative Zoology, Harvard University. (CC BY 2.5; K. N'Diaye. Evolutionary History of a Gene Controlling Brain Size. PLoS Biol 2(5): e13...Thumbnail: Primate skulls provided courtesy of the Museum of Comparative Zoology, Harvard University. (CC BY 2.5; K. N'Diaye. Evolutionary History of a Gene Controlling Brain Size. PLoS Biol 2(5): e134. DOI: 10.1371/journal.pbio.0020134).