Martin Chalfie, University Professor and former chair of the Department of Biological Sciences at Columbia University, shared the 2008 Nobel Prize in Chemistry with Osamu Shimomura and Roger Y. Tsien for his introduction of Green Fluorescent Protein (GFP) as a biological marker. Professor Chalfie was born in Chicago, Illinois, obtained Ph.D. in Physiology with Robert Perlman from Harvard University, and did postdoctoral research with Sydney Brenner at the MRC Laboratory of Molecular Biology, Cambridge, England. He joined the faculty of Columbia University as an Assistant Professor in 1982. His research uses molecular, genetic, and electrophysiological means to address how different types of nerve cells acquire and maintain their unique characteristics and how sensory cells respond to mechanical signals. This research includes studies on neuronal degeneration, microtubule structure and function, neuronal outgrowth, mechanosensory transduction and its modulation, transcriptional robustness, neuronal circuitry, and neuronal ensheathment.