1. Howard Hughes Medical Institute, Department of
Molecular Biology and Center for Computational and Integrative Biology,
Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
2. Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
3. Åbo Akademi University, Department of Biosciences, Artillerigatan 6, FI-20520 Åbo, Finland
4. Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States