The road to synthetic multicellularity

Multicellularity is a crucial innovation that has taken place independently at least 25 times in the evolution of life on our planet. Uncovering the evolutionary rules associated to the emergence of this transition has been partially achieved thanks to a combination of comparative cell biology, phylogenetic, palaeobiology and genomic studies of primitive model organisms. An alternative path to this goal is the use of synthetic and systems approximations including both experimental and mathematical models. An ambitious research program should consider not only those aspects related to genetic regulatory networks and the conditions for the emergence of developmental plans and life cycles, but also crucial aspects associated to the environmental context. Here we review several key results, formulate a list of open problems and suggest potentially relevant avenues to follow at the crossroads between ecology, evolution and development.