Comparative single-cell regulome reveals evolutionary innovations in neural progenitor cells during primate corticogenesis
The cellular and genetic mechanism underlying the human-specific features of cortex development remains unclear. We generated a cell-type resolved atlas of transcriptome and regulome of the developing macaque and mouse prefrontal cortex, and conducted evolutionary analyses with the published complementary human data. We discovered a primate-specific expansion of two neural progenitor subclasses, glia-committed radial glia (RG) and truncated RG. Specifically, the human neural progenitors show extensive transcriptional rewiring in the growth factor and extracellular matrix pathways. Expression of the human-specific progenitor marker ITGA2 in the cortex of fetal mouse promotes progenitor proliferation and an increased upper-layer neuron proportion. We demonstrate that these transcriptional divergences are primarily driven by the activity changes of the distal regulatory elements in the genome. Markedly, the chromatin regions with human-gained accessibility enrich the human-fixed sequence changes, as well as sequence polymorphisms associated with intelligence and neuropsychiatric disorders. Our results uncover evolutionary innovations in neural progenitors and gene regulatory mechanism during primate cortex evolution.