Fundamental limits to the precision of multicellular sensing

Recent experiments suggest that connected cells detect shallower chemical gradients together than alone, and that this enhanced sensitivity is lost when cell-to-cell communication is blocked. Here we derive the fundamental limits to the precision of gradient sensing by a chain of communicating cells. We show using linear response theory how precision is limited by the external diffusion of signaling molecules, by the exchange of messenger molecules between cells, and by the number of cells in the chain. We discuss how our predictions could be compared with ongoing experiments.