1. Department of Dermatology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
2. Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032
3. Center for Computational Biology and Bioinformatics, Columbia University Medical Center, New York, NY 10032
4. Department of Systems Biology, Columbia University, New York, NY 10032
5. Howard Hughes Medical Institute, Chevy Chase, MD 20815