Bayesian Inference of Chromatin Looping

With the advent of new imaging technologies, we are increasingly able to observe the highly dynamic organization of chromatin in real time. An especially interesting class of experiments being developed in several groups tracks two genomic loci on the same chromosome, in the hope of gaining mechanistic insight into the mechanisms underlying their interaction. Specifically the formation of chromatin loops by a mechanism known as loop extrusion is assumed to be a central motif in the regulation of genome structure. We developed a Bayesian inference algorithm to detect sustained contacts in two-particle tracking experiments, thereby uncovering the dynamics of chromatin loops. While the biological insight from this application alone is considerable, the algorithm itself is very general and is immediately applicable to other experiments, e.g. to study the interaction of enhancers and promoters.