About the Authors
Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: KB LY RAL STK DW. Performed the experiments: KB LY RAL STK. Analyzed the data: KB JDH. Contributed reagents/materials/analysis tools: NW JF. Wrote the paper: KB LY RAL STK JDH NW DW.