About the Authors
Department of Biology, Boston University, Boston, Massachusetts, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: KTRW ALM. Performed the experiments: KTRW ALM. Analyzed the data: KTRW ALM JFAT. Contributed reagents/materials/analysis tools: JFAT. Wrote the paper: KTRW ALM JFAT.