Human-specific ARHGAP11B increases size and folding of primate neocortex in the fetal marmoset

Neocortex in the fetal brain Along the path of human evolution, gene duplication and divergence produced a protein, ARHGAP11B, that is found in humans but not nonhuman primates or other mammals. Heide et al. analyzed the effects of ARHGAP11B gene expression, under control of its own human-specific promoter, in the fetal marmoset (see the Perspective by Dehay and Kennedy). In the early weeks of fetal growth, the gene drove greater elaboration of neural progenitors and neocortex than is evident in the normal fetal marmoset. ARHGAP11B expression may be one cause of the more robust neocortex that characterizes the human brain. Science , this issue p. 546 ; see also p. 506