1. Computer Science and Artificial Intelligence Laboratory, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
2. Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
3. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E1, Canada.
4. Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
5. Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA.
6. Department of Pharmacy University of Toronto, Toronto, ON M5S 3E1, Canada.
7. Center for Ecology and Evolutionary Biology, 5289 University of Oregon, Eugene, OR 97403, USA.
8. Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA.