Abstract
Programmed cell death (PCD) is widespread during neurodevelopment, typically countering the surpluses of neuronal production. We examined, in the Drosophila olfactory system, the potential of cells fated to die to contribute to circuit evolution. Inhibition of PCD is sufficient to generate many new cells that express neural markers and exhibit odor-evoked activity. These “undead” neurons express a subset of olfactory receptors, enriched for recent receptor duplicates, and including those normally found in other chemosensory organs and life-stages. Moreover, undead neuron axons integrate into the olfactory circuitry in the brain. Comparison of homologous olfactory lineages across drosophilids reveals natural examples of fate changes from death to a functional neuron. These results reveal the remarkable potential of alterations in patterns of PCD to evolve novel neural pathways.
Footnotes
Abstract revised; secondary antibodies added to Table S2. Minor formatting changes.