About the Authors
Division of Biology, University of California San Diego, La Jolla, California, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: KBM AEP. Performed the experiments: KBM SGP VM AEP. Analyzed the data: KBM SGP VM AEP. Contributed reagents/materials/analysis tools: KBM SGP VM AEP. Wrote the paper: KBM AEP.