Figure EV1. Schematic of potential replication products from G4 and iM‐containing templates.

Position of the origin of replication is marked as ‘ori’ from which replication initiates through sequence‐specific replisome loading. Two forks initiate from the origin and generate one longer rightward moving fork of 8.2 kb (‘Leading strand 1’) and one shorter leftward moving fork of 1.5 kb (‘Leading strand 2’). Lagging strand products are synthesised as short Okazaki fragments. The multiple cloning site (indicated by a red star) is positioned 3 kb downstream of the origin and was used to insert various G4 or iM‐forming sequences into the template. This means that only the rightward moving fork would encounter them and therefore ‘leading strand 2’ can serve as an internal control. Under conditions of replication stalling, helicase‐polymerase uncoupling may occur which may be associated with intrinsic repriming at the site of fork stalling. Replication products may also break at the site of the insert during or after replication.