1. Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
2. Center for the Study of Biological Complexity, Virginia Commonwealth University, 1000 West Cary Street, Richmond, VA 23284, USA.
3. Genomics Solution Unit, Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA 95051, USA.
4. Department of Computer Science, Virginia Commonwealth University, 401 West Main Street, Richmond, VA 23284, USA.