MorphoBlock Programming: a way to model and simulate morphogenesis of multicellular organisms.

International audienceMorphogenesis is a key phenomenon occurring in multicellular organisms. It involves many mechanisms at the cellular level like differentiation, migration, division or communication between cells. The study of such complex living systems is difficult despite the improvement of confocal microscopes including those working with four dimensions (space and time). Observation has been much enhanced but comprehension of the organization is yet to come. In virtuo simulation allows focus on the study of the organization mechanisms (in virtuo is an extension of the in silico paradigm where the user is a central actor of the simulation). Hence, the use of a computer program reproducing some parts of the morphogenesis phenomenon is complementary to real experimentation. Moreover, modelling using a programming language facilitates exchange of knowledge between biologists by reducing the ambiguity compared with text or diagrams. To help the comprehension of morphogenesis, we have developed software based on a multiagent system that reproduces the following mechanisms: cell migration, cell division, cell apoptosis, cell signalling, cell differentiation and cell polarization. In our software, an agent is called a MorphoBlock, which means a block of morphogenesis. By using these simple MorphoBlocks, the simulations show different kinds of dynamics and generate structures that can be compared, from an abstract point of view, to the formation of multicellular organisms. In this paper, we focus on two main parts of our software: first the shape, behaviour and parameters of a MorphoBlock; and second the observation of morphogenesis from simulations with many MorphoBlocks