Deformations of living tissues during animal development stem from an intricate interplay of cell shape changes, cell division, cell migration, cell intercalation, and cell differentiation that obfuscates the underlying physical principles. For this reason, a joint experimental and theoretical effort has recently established a simpler model of tissue folding: the inversion whereby the embryos of the green alga Volvox turn themselves inside out and which results from cell shape changes only.
In this talk, I will develop a model of tissue folding in which these cell shape changes appear as variations of the intrinsic stretches and curvatures of an elastic shell. I will show how this model reproduces Volvox inversion quantitatively, reveals the spatio-temporal regulation of different biological driving processes, and explains mechanically the arrest of inversion observed in mutants. I will close by discussing some of the outstanding problems, both biological and physical, that this work opens up.
Biography:
Pierre Haas is a theoretical biophysicist working in the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge. His research is supported by a Nevile Research Fellowship in applied mathematics from Magdalene College, Cambridge.