On the left is a snapshot of single histone molecules (red) inside a cell nucleus (dotted line). On the right, we see the trajectories of these molecules’ movement over time. The colors show the path they travel, and each trajectory changes color to give an impression of time passing. Credit: Massachusetts Institute of Technology

Gene expression is controlled, in part, by the interactions between genes and regulatory elements located along the genome. Those interactions depend on the ability of chromatin—a mix of DNA and proteins—to move around within a crowded space.…