sentences:  In the event of deregulated Fen1/DNA polymerase δ activity, the cell uses an alternative mechanism to generate and process long flaps by using Dna2, which has both helicase and nuclease activities.The nuclease activity of Dna2 is required for removing these long flaps, leaving a shorter flap to be processed by Fen1.Electron microscopy studies indicate that nucleosome loading on the lagging strand occurs very close to the site of synthesis.