Modelling an Organism: Slime Mould Morphogenesis

Stan Maree

Department of Mathematics University of British Columbia, Canada

Upon starvation, solitary amoebae of the cellular slime mould Dictyostelium discoideum aggregate and form migrating multicellular slugs, which behave as a single organism. Slugs show a pronounced thermo- and phototaxis, which direct them towards the soil surface, where migration halts and the whole process culminates in the formation of a fruiting body consisting of a globule of spores on a slender stalk. We have simulated the whole developmental process using a hybrid cellular automata/partial differential equation model. In the model, individual cells are represented as a group of connected automata, i.e. the basic scale of the model is subcellular. With our model we have been able to reproduce and understand the dynamics that emerge during the Dictyostelium lifecycle. I will show that cyclic AMP signalling, differential adhesion, cell differentiation and production of extracellular matrix are in fact sufficient to produce the dynamics of the morphogenesis, and how the entire development, including many self-organizing and self-correcting properties, is enacted by means of the above mentioned building blocks.