About the Authors
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: MW-LP RAK HLP. Performed the experiments: MW-LP RAK. Analyzed the data: MW-LP RAK HLP. Contributed reagents/materials/analysis tools: MW-LP RAK. Wrote the paper: MW-LP RAK HLP.