Title 

Physics of Tissue Development: How Defects Can Organize Morphogenesis

Abstract

During development, living tissues undergo striking shape changes, sometimes even altering their topology. For example, in gastrulation a sphere of cells folds into a tube, while in the regeneration of the freshwater polyp Hydra, a spherical cell aggregate elongates, forms a head and a foot, and eventually grows tentacles. Such dramatic transformations arise from the collective dynamics of cells, which behave as active units capable of generating mechanical stress. A key feature underlying these processes is the orientational order displayed by many tissues. In this talk, I will present a physical framework that treats tissues as active polar fluids and show how a hydrodynamic description can capture their behavior. I will illustrate this approach with examples where defects in the orientational order are central for guiding development. I will then discuss how such defects can be stabilized and organized in active fluids, and finally consider the influence of fluctuations on these dynamic systems.

If you wish to attend this seminar online, please send an email to m.t.pham@uva.nl to receive the zoom-link.