Fraser also is the Anna L. Rosen Professor of Biology at Cal Tech. He is well known for developing new imaging techniques and experimental strategies that allow single-cell resolution studies of key biological processes that occur in intact organisms early in their development. His group has refined cell micro-injection techniques to permit the rapid and reliable injection of single cells in living embryos with vital dyes or other re-agents. The marked cell and its progeny then can be followed using video, laser scanning confocal, laser scanning two-photon or magnetic resonance microscopy. These powerful methods have been used to examine the role of cell interactions, intercellular signals and gene regulatory mechanisms in model organisms from the frog to the mouse.