NvashA function reveals temporal differences in neural subtype generation in cnidarians

Understanding how cnidarians pattern their nervous systems can provide insight into the ancestral mechanisms of neurogenesis that are shared with bilaterians, shedding light on the evolution of nervous systems. While previous studies revealed conserved mechanisms for neural induction, progenitor selection, and spatial patterning mechanisms between cnidarians and bilaterians, less is known about how distinct neuronal subtypes are specified over time in cnidarians. We utilized single-cell mRNA sequencing to profile NvashA-expressing cells across embryonic and planula-larva stages of Nematostella vectensis neurogenesis, and functional experiments to demonstrate that different neuronal fates are arising in a temporal pattern during embryonic and larval stages. These data demonstrate that there is a temporal component to neuronal patterning in Nematostella, which is consistent with mechanisms of neurogenesis observed in bilaterian model systems. These data further strengthen the conclusion that cnidarian nerve nets and complex bilaterian centralized nervous systems evolved from a common ancestor that utilized similar spatiotemporal patterning strategies to generate neuronal cell type diversity.