He received his Ph.D. in 2002 from MIT, where he worked in the laboratory of Dr. H. Robert Horvitz on programmed cell death in C. elegans. His work now focuses on regeneration, using planarian flatworms as a model system. He began this work as a Helen Hay Whitney postdoctoral fellow in the lab of Dr. Alejandro Sánchez Alvarado at the University of Utah Medical School. He performed the first RNA interference-based screen in planarians, helping to establish planarians as a new molecular genetic system. Planarians can regenerate any missing part of their body, and Reddien’s laboratory studies genes required for regeneration. This work has led to the discovery of stem cell regulatory genes and genes that promote regeneration.