Mostly Absent

Maps called them architecture — arcs drawn solid from enhancer to gene.

Sixty-five thousand nine hundred now each carry a fraction: how often the two ends touch in a living mouse stem cell.

Average: one point two. Strongest: a quarter — gone three times out of four.

CTCF pairs hold a little longer. The regulatory ones stay under one.

The page keeps the arcs. The cell mostly does without them.