1. Present address: Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
2. Present address: Internal Medicine Residency Program, University of Connecticut Health Center, Farmington, CT 06030, USA.
3. Present address: School of Medicine, University of Washington, Seattle, WA 98195, USA.
4. Present address: Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114, USA.
5. Department of Biology, Wesleyan University, Middletown, CT 06459, USA