Characterization of solid-like motion in an active polymer model for chromatin

Recently we suggested transient disorder-to-order transition induced by active forces (F) as a physical mechanism for transcription-associated suppression in chromatin motion. Here we present the dynamical characterization of individual loci exhibiting solid-like order in the active copolymer model for chromatin which was employed in our previous study. In a particular range of F, where the solid-like order emerges, a subpopulation of the active loci is found to undergo pronounced suppression in the dynamics. We demonstrate direct correlation between the suppressed dynamics and the ordering of active loci, revealing that the subpopulation with dynamic suppression corresponds to a large microphase of active loci which is segregated from a smaller one. Remarkably, the suppressed motion of active loci shows coherence that reflects solid-like character. This characterization scheme based on our theoretical study may be useful for assessing potential solid-like character from experimental measurements of chromatin dynamics.