About the Authors
Department of Biochemistry, Stanford University, Stanford, California, United States of America
Stanford Genome Technology Center, Palo Alto, California, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: TKN RWD. Performed the experiments: TKN. Analyzed the data: TKN. Contributed reagents/materials/analysis tools: TKN RWD. Wrote the paper: TKN.