1. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2. Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA.
3. Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
5. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.