Ramaekers, A., Claeys, A., Kapun, M., Mouchel-Vielh, E., Potier, D., Weinberger, S., Grillenzoni, N., Dardalhon-Cuménal, D., Yan, J., Wolf, R., Flatt, T., Buchner, E., Hassan, B.A. (2019). Altering the Temporal Regulation of One Transcription Factor Drives Evolutionary Trade-Offs between Head Sensory Organs.  Dev. Cell 50(6): 780--792.e7.

FBrf0243494

Research paper

Size trade-offs of visual versus olfactory organs is a pervasive feature of animal evolution. This could result from genetic or functional constraints. We demonstrate that head sensory organ size trade-offs in Drosophila are genetically encoded and arise through differential subdivision of the head primordium into visual versus non-visual fields. We discover that changes in the temporal regulation of the highly conserved eyeless/Pax6 gene expression during development is a conserved mechanism for sensory trade-offs within and between Drosophila species. We identify a natural single nucleotide polymorphism in the cis-regulatory region of eyeless in a binding site of its repressor Cut that is sufficient to alter its temporal regulation and eye size. Because eyeless/Pax6 is a conserved regulator of head sensory placode subdivision, we propose that its temporal regulation is key to define the relative size of head sensory organs.