Human-specific morphoregulatory signatures in basal radial glia characterise neocortex evolution

As the seat of our cognition, the human neocortex is an object of immense fascination. Human neocortex expansion during evolution has been attributed to an increase in the proliferative capacity of neural progenitor cells during development, particularly basal radial glia. Despite their evolutionary relevance, the genomic changes driving human basal radial glia biology remain uncharacterised. We use comparative chromatin and transcriptional profiling of neural progenitor cells isolated from gorilla, chimpanzee and human cerebral organoids to identify cis-regulatory elements that have gained activity in humans. Focusing specifically on basal radial glia, we discover that morphoregulatory enhancer activity and gene expression signatures distinguish human basal radial glia from other great apes. Functional analysis of the morphoregulatory genes FAM107A and CNGA3 in human organoids reveals that these genes contribute to the morphological complexity of human basal radial glia. Taken together, our inter-species comparison of basal radial glia suggests that human-specific morphoregulatory signatures characterise neocortex evolution.