Arthur D. Lander (University of California, Irvine; SFI External Professor)
Abstract. Our bodies arise through a process of controlled growth that can exhibit great speed and precision. That this happens is remarkable given that the basic units of growth—cells and parts of cells—are self-reproducing, and therefore naturally increase in an exponential fashion. Exponential processes are both easily destabilized and inherently sensitive to perturbations, making them especially difficult to control. What general principles does nature use to tackle this problem? Although some specific molecules and mechanisms have been implicated in the feedback regulation of growth, we still have a very limited understanding of what information is being fed back, and for what purpose. In many cases we know more about what is not being fed back than what is: for example, there are many organs or tissues whose final sizes are known to be specified in a manner independent of body size, independent of cellular growth rate, independent of elapsed time, and independent of cell size. In my talk, I will discuss some of the things that modeling and experiments have recently revealed about design principles underlying biological growth control, focusing in particular on the roles played by regulated cell lineage progression.