Dr Julian Hart Lewis FRS
Emeritus Scientist (formerly Head, Vertebrate Development Laboratory), Cancer Research UK London Research Institute
Julian Lewis is distinguished by the elegance and foresight with which he combines experimental and theoretical approaches to analyse the mechanisms that regulate animal development. He has a sustained record of making pioneering advances in studying the processes and logic that underlies the patterning of vertebrate embryos, with particular emphasis on timing mechanisms. In particular, he cloned vertebrate Notch ligands and used them to demonstrate that Notch signalling functions in vertebrates to regulate the timing of neural differentiation, thereby ensuring that neural stem/progenitor cells are maintained to produce the many and diverse cells of the vertebrate nervous system. Also of particular note is his modelling the oscillatory circuit (the "segmentation clock") that regulates regular segmentation of the vertebrate body axis. He showed experimentally that synchronisation of neighbouring cycling cells is Notch-mediated, and then modelled the clock circuitry via delayed negative-feedback to demonstrate the critical importance of delay kinetics (and not component concentrations) in defining clock periodicity.