show Abstracthide AbstractGenetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates, including more recently the genomes of archaic hominins. Not all regions of the genome, however, areequally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2accounts for ~1% of autism cases and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. We reconstructed the evolutionary history of the locus and identified BOLA2 (bolA family member 2) as a gene duplicated exclusively in Homo sapiens.