The Pax6 master control gene initiates spontaneous retinal development via a self-organising Turing network

Understanding how complex organ systems are assembled from simple embryonic tissues is a major challenge. Across the animal kingdom a great diversity of visual organs are initiated by a master control gene called Pax6, which is both necessary and sufficient for eye development1-6. Yet precisely how Pax6 achieves this deeply homologous function is poorly understood. Here we show that vertebrate Pax6 interacts with a pair of morphogen-coding genes, Tgfb2 and Fst, to form a putative Turing network7, which we have computationally modelled. Computer simulations suggest that this gene network is sufficient to spontaneously polarise the developing retina, establishing the eyes first organisational axis and prefiguring its further development. Our findings reveal how retinal self-organisation may be initiated independent of the highly ordered tissue interactions that help to assemble the eye in vivo. These results help to explain how stem cell aggregates spontaneously self-organise into functional eye-cups in vitro8. We anticipate these findings will help to underpin retinal organoid technology, which holds much promise as a platform for disease modelling, drug development and regenerative therapies.