Andrew Z.Fire, of both the Carnegie Institution of Washington and the Johns Hopkins University; Dr. Craig C. Mello, of the University of Massachusetts Medical School; Dr. Thomas Tuschl, formerly of the Max-Planck Institute for Biophysical Chemistry in Goettingen, Germany, and most recently of The Rockefeller University; and Dr. David Baulcombe, of the Sainsbury Laboratory at the John Innes Centre in Norwich, England - For contributions to discoveries of novel mechanisms for regulating gene expression by small interfering RNAs (siRNA).