Recent advances in our understanding of central and peripheral nervous system progenitors.

Several decades of intense research provided us with a grand framework describing the emergence of neurons in central (CNS) and peripheral (PNS) nervous systems. However, the specifics of molecular events and lineage control leading to a plethora of neuronal subtypes stayed largely unclear. Today, the advances in single cell omics, sample clearing and 3D-microscopy techniques, brain organoids, and synaptic connectivity tracing enabled systematic and unbiased understanding of neuronal diversity, development, circuitry and cell identity control. Novel technological advancements stimulated the transition from conceptual scheme of neuronal differentiation into precise maps of molecular events leading to the diversity of specific neuronal subtypes in relation to their locations and microenvironment. These high-resolution data opened a set of new questions including how transcriptional and epigenetics states control the proportionality of neuronal subpopulations or what are the evolutionary mechanisms of origin of different neuronal subtypes. In this review, we outline the most recent advancements in our understanding of how the neuronal diversity is generated in CNS and PNS and briefly address the challenges and questions arising in the field of neurogenesis.