Faculty Member

Peter W.

Peter Reddien

Peter Reddien

Member, Whitehead Institute

Professor of Biology, MIT

Howard Hughes Medical Institute Investigator


Reddien Lab


Our lab is focused on understanding how regenerative organisms regrow missing body parts. We utilize molecular genetic techniques to study the cellular and molecular events that control regeneration. Using planarians, a classic regeneration model system, we determined that the combination of positional information and stem cells can enable regeneration of missing body parts.

Regeneration of tissues and organs is one of the great mysteries of biology. Whitehead Member Peter W. Reddien works to shed light on that mystery through research on multiple regenerative organisms, with a focus on the planarian Schmidtea mediterranea. Planarians are flatworms with regenerative powers that have captured the imagination of biologists for more than a century. Reddien led the first large-scale study of gene function in planarians, discovering many genes needed for regeneration.

New tissues and organs in planarian regeneration are produced by neoblasts—adult stem cells that share certain characteristics with embryonic stem cells and can differentiate into essentially all cells found in adult animals. A similar process occurs in normal uninjured adult planarians, in which neoblast progeny cells continually replace aged cells.

Reddien's lab has found that some neoblasts are pluripotent stem cells, providing the cellular basis for new tissue production in planarian regeneration. They also discovered that extensive specialization of neoblasts occurs, generating progenitors for the diverse cell types of the body.  Work on neoblasts informs how stem cells are regulated in the context of injury and tissue maintenance, and has identified roles for many conserved molecules.

How do neoblasts determine what cell types to make? Reddien's lab has identified positional information that is required for animals to regenerate the correct tissues, and proposes that such information (in the form of position control genes) constitutes a coordinate system that instructs the biology of stem cells. Inhibition of position control genes, including those associated with Wnt signaling, can result in dramatic regeneration abnormalities, such as the formation of a head instead of a tail. Unexpectedly, the Reddien lab found that this positional information is harbored primarily in one tissue: muscle. The Reddien lab studies the signals that come from muscle to guide regeneration and how regenerative progenitors respond to extrinsic cues to form new organs and tissues.

Reddien became a Whitehead Member and joined the MIT faculty in 2005. He is now Professor of Biology and Associate Head of the MIT Department of Biology, as well as Associate Director at Whitehead. He completed his undergraduate studies in molecular biology at the University of Texas at Austin, then obtained his PhD in biology from Massachusetts Institute of Technology, followed by postdoctoral work with Alejandro Sanchez Alvarado (now at the Stowers Institute).

Selected Achievements

  • Fellow, Helen Hay Whitney Foundation (2003)
  • Rita Allen Scholar Award (2006)
  • Searle Scholar Award (2006)
  • Smith Family Scholar Award (2006)
  • Keck Distinguished Young Scholar (2008)
  • Howard Hughes Medical Institute (HHMI) Early Career Scientist (2010)
  • Led the first large-scale study of gene function during regeneration in planarian flatworms
  • HHMI Investigator (2013)

© Whitehead Institute for Biomedical Research              455 Main Street          Cambridge, MA 02142