1. Horizon Discovery Inc., 245 First Street, Cambridge, MA 02142, USA.
2. U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA.
3. University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA.
4. Bioinformatics Program, Boston University, 20 Cummington Street, Boston, MA 02215, USA.