Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America.|Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America.|Department of Physics, California Institute of Technology, Pasadena, California, United States of America.|Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America.|Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America.