1Departments of Dermatology and Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia Pennsylvania 19104
2Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
3Bioinformatics Core, University of Pennsylvania, Philadelphia, Pennsylvania 19104
4Gastroenterology Division, Department of Medicine, Abramson Cancer Center and Family Research Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
5Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104