1. Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
2. Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA.
3. Department of Computer Science, Stanford University, Stanford, CA 94305, USA.
4. Department of Computer Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
5. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
6. Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
7. Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA.
8. Genome Biology, The European Molecular Biology Laboratory Heidelberg, 69117 Heidelberg, Germany.