Seeing is Believing, or How GFP Changed My Approach to Science

The field of "Developmental Biology" has dramatically changed over the past three decades. While genetic analysis had been center stage in the 1980s and continues to be a corner stone for investigations, the introduction of green fluorescent protein (GFP) in the 1990s has allowed us to look into living, developing embryos, and see how cells form tissues and how organ morphogenesis proceeds in real time. The introduction of protein binders into developmental studies some years ago has raised the precision yet another step, since it will allow the manipulation and study of how proteins function in real time. This chapter is a personal account on how GFP has, and how protein binders may, change the design of studies in the field of developmental biology.