1. Research Unit Stem Cell Dynamics, Helmholtz Center Munich–German Research Center for Environmental Health (GmbH), Neuherberg, Germany;
2. Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zurich, Basel, Switzerland;
3. Institute of Clinical Molecular Biology and Tumor Genetics, Helmholtz Center Munich–German Research Center for Environmental Health (GmbH), Munich, Germany;
4. Institute for Developmental Genetics, Helmholtz Center Munich–German Research Center for Environmental Health (GmbH), Neuherberg, Germany; and
5. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY