By observing the activity of a protein complex in real time, researchers have uncovered new evidence for a long-standing theory. EDITOR’S CHOICE IN CELL & MOLECULAR BIOLOGY The paper M. Ganji et al., “Real-time imaging of DNA loop extrusion by condensin,” Science, doi:10.1126/science.aar7831, 2018. How does a human cell neatly pack more than 2 meters’ worth...