Figure 4.

Schematic representation of lagging and leading strand replication. DNA polymerase Polα with a single RNA primer initiates synthesis of leading strand, which is subsequently replaced by Polε for further elongation. The lagging strand is copied through discontinuous Okazaki fragments from multiple primers. RNA primers are degraded and the gaps filled by Polδ followed by ligation of discontinuous fragments. The gap at 5′ end remains unfilled, leading to a non-replicated terminal region. Adapted from [7].