Fig. 4.

Value of ɣ obtained using Hi-C is consistent with a tension globule in which loops form by diffusion. (A) Value of ɣ for a polymer after condensation varies as the ratio of internal to external forces, R, is changed. (B) Condensation of a 10-Mb tension globule over time. (C) Contact probability vs. distance for 450 simulated tension globules with a length of 10 Mb. In each case, a power law is seen for distances between 20 kb and 800 kb. Mean ɣ = 0.73, SD = 0.07. (D) Simulation of a region of chromosome 4 in GM12878 (chromosome 4: 20.3–22.6 Mb). The experimental data exhibit four loop domains (Left) and can be recapitulated (Right) using a tension globule containing four loops (black arcs) which is tethered at both ends (SI Appendix). Contact domains form spontaneously.