1. Department of Genetic Medicine and Development (C.R.C., J.-D.V., S.N.), University of Geneva Medical School, 1211 Geneva 4, Switzerland
2. Genomics Platform (O.S., P.D.), National Center of Competence in Research Frontiers in Genetic, University of Geneva, 1211 Geneva 4, Switzerland
3. Institut de Génétique et de Biologie Moléculaire et Cellulaire and Institut Clinique de la Souris (P.C.), Collège de France, 67404 Illkirch Cedex, France