Human-specific alterations in brain cellular proportions

How do genes drive the development of cell types that build the human brain and give rise to cognition? More specifically, how does human cognitive behavior emerge from a set of evolutionarily adapted genomic programs? The human brain is comprised of heterogenous cell types and understanding the gene expression patterns and chromatin states within each of these cell types can provide important insights into both brain evolution as well as the development of cognitive disorders. We have used single cell genomics to compare human and nonhuman primate brains to uncover human brain innovations including changes in the proportions of immature oligodendrocytes in the neocortex. We have recapitulated this result in vitro using stem cell derived models from humans and nonhuman primates. Together, these data highlight the complex intersection of cellular genomics with brain evolution and function.