In this project the investigators will explore phenomena that span the tree of life: from metabolism in bacteria, through the determination of cell fate in embryonic development, to coding and computation of sensory information in the brain. They have identified broad theoretical problems which cut across the traditional biological divisions of organism and system: Do living organisms operate near the limits set by the laws of physics as they gather and process information? Can the detailed microscopic model of an organism, its wiring diagram be understood from the finite set of observations that can be made on how it behaves? How do organisms set the parameters that govern their function (i.e. how do they learn from experience)? These questions will be given a mathematical form, which will guide a search for answers in terms of general principles, in the tradition of physics, that will apply across disparate biological domains. The participants in the project will assemble into subgroups to attack instances of these problems. The individual projects will have unusual scope: as an example, the question whether the complex statistics of biological behavior can be captured in a learnable mathematical model will be asked in very similar terms both of spiking retinal neurons, and of the antibody sequence repertoire of individual zebrafish. These questions will be answered in the light of accurate data and the work will involve a close partnership with many experimental groups in fields ranging from bacteriology to human perceptual psychology. The product of these interactions will be the design of novel experiments and the creation of novel data analysis methods in order to address clearly formulated mathematical questions of broad significance. An important component of this project is the training of a new generation of physicists for whom the development of a theoretical understanding of biological systems is a central part of their discipline. The graduate students and postdoctoral scholars who pass through the group will learn by example how to pursue that goal in a way consistent with the intellectual rigor and traditions of physics.
