Second, some—but only some—cell classes show area-specific patterns of gene expression that likely reflect their developmental history. This trend was strongest among neurons, astrocytes, and ependymal cells; by contrast, oligodendrocytes, vascular cells, and immune cells exhibited similar gene expression patterns across brain regions. The territories defining these gene expression domains corresponded closely to those marked out by embryonic morphogens, and spatial differences in adult expression patterns correlated with persistent expression of developmental transcription factors. This suggests that transcription factor networks induced in early development by local morphogens result in heritable regulatory states, which in turn are relayed into the diversification of terminal neuronal and astrocytic types specific to each brain region.
