Modeling of human chromosome 14. (Left) MCMC5C model of human chromosome 14 from the Hi-C dataset. The midpoints of the 3D-FISH probes used by Lieberman-Aiden et al.  are annotated as L1, L2, L3, L4 and were designed such that in consecutive order the probes alternate between compartments. The structure adopts a loosely defined spiral form which brings the probes from within either compartment (A: L1 and L3, B: L2 and L4) in closer physical proximity than between pairs of probes across compartments. (Right) Distances inferred by MCMC5C correspond to physically-measured distances. X-axis: average Euclidean distance in the ensemble of 250 structures sampled by MCMC5C. Y-axis: median 3D-FISH physical distance measured by Lieberman-Aiden et al. . Even though probe L3 is located between probes L2 and L4 in the linear sequence, probes L2-L4 are closer together in the model than L3-L2, indicating preferential organization of probes belonging to the same compartment (B) than across compartments (A-B) as initially reported in Lieberman-Aiden et al. .