Physics for maggots

by William Bialek Princeton University (Princeton University)

Wednesday 7 May 2025, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica-Ed. Marconi)

The development of a single cell into a fully functional organism is one of Nature’s most extraordinary phenomena. In a fruit fly, the larva—a maggot—can walk away from the discarded egg shell just 24 hours after the egg is laid. Even more strikingly, if we measure the concentrations of fewer than a dozen crucial molecular species we see a “blueprint” for the segmented body plan of the maggot after just three hours.   This process is extraordinarily precise, yet the relevant information is encoded by molecules that are present only at very low concentrations, and hence the process should be noisy.  I’ll describe a combined theory/experiment effort to explore this problem, motivating a physical principle: the underlying genetic network is tuned to extract as much information as possible from a limited number of molecules. The parameter-free predictions of this theory provide a successful account of detailed, quantitative experiments.