1. Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
2. Department of Developmental Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA.
3. Departments of Applied Physics and Bioengineering, Stanford University, and Howard Hughes Medical Institute, Stanford, CA 94305, USA.
4. Department of Computer Science, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
5. Ludwig Center for Cancer Stem Cell Research and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.