The authors thank O. Juez, R. Jodhani and C. Araneo for technical assistance and the MIT Biomicro Center, the Harvard Medical School Biopolymers Facility, and the Broad Institute Genomics Platform for sequencing. The authors acknowledge funding from an NSF Graduate Research Fellowship to M.W.S.; an NWO Rubicon Fellowship to M.A.; 1R01HG010372 (C.A.C.); DARPA HR0011-17-2-0049, NIHRM1 HG009490, R01 EB022376, R35 GM118062, HHMI (D.R.L.); 1RO1HG008363, 1R01HG008754 (D.K.G.); 1K01DK101684, the Human Frontier Science Program, NWO, Brigham Research Institute, Harvard Stem Cell Institute, and American Cancer Society (R.I.S.).

Reviewer information

Nature thanks D. Durocher, R. Platt and the anonymous reviewer(s) for their contribution to the peer review of this work.