Lecturer: Prof. Erez Braun, Technion-Israel Institute of Technology
Abstract:
The current picture of animal morphogenesis relies on biochemical patterning and its robustness is typically attributed to the presence of a well-defined hierarchy of forward-driven processes, such as threshold-crossing cellular processes and the development of symmetry-breaking fields. Is it possible to modulate the course of animal morphogenesis and direct its developmental trajectory on demand? We demonstrate that an external electric field can be tuned to drive morphogenesis in Hydra regeneration, backward and forward, around a critical point in a controlled manner. A controlled drive of morphogenesis allows multiple re-initiation of novel developmental trajectories for the same tissue. We show that calcium spatial fluctuations serve as an integrator field of the underlying electrical-mechanical processes and drive the morphological dynamics. Utilizing external electric fields to hold the Hydra tissue at the onset of morphogenesis, we study fluctuations and correlations of the calcium field in conjunction with morphology near a critical morphological transition. It allows us to gain a statistical view of the dynamics; the normalized calcium spatial fluctuations exhibit a universal non-Gaussian shape distribution, across tissue samples and conditions, suggesting a global constrain over these fluctuations. Studying the dynamics at the onset of morphogenesis opens a new vista on this process and paints a picture of development analogous to a dynamical phase transition.