Fig. 2: Polymerase usage and replication initiation across the human genome.

a Profiles of the relative reads for Polε and Polα mutants on the Watson and Crick strand for each 1 kb bin. Orange: Polε (POLE1-M630F). Blue: Polα (POLA1-Y865F). A representative region of chromosome 3 is shown. Data were smoothed with a moving average (m = 3; see “Materials and Methods”). b Schematic representation of predicted Polε and Polα profiles at a site of replication initiation and termination. Orange: leading strand. Blue: lagging strand. c Top: smoothed data from panel a (moving average, m = 30) provides a map of polymerase usage. Bottom: plot of the calculated initiation index. Positive values (green) represent increased initiation activity. Negative values (grey) represent increased converging fork termination. d Definition of the initiation index (see materials and methods for further details). ‘Δ’ indicates the differential between neighbouring bins, e.g. at location x, Δε(x) is defined as ε(x + 1)-ε(x).