Original sentence: In NHEJ, DNA Ligase IV, a specialized DNA Ligase that forms a complex with the cofactor XRCC4, directly joins the two ends.In the final step there is crossover by means of RecA-dependent homologous recombination.Recombinational repair requires the presence of an identical or nearly identical sequence to be used as a template for repair of the break.Three mechanisms exist to repair DSBs: non-homologous end joining (NHEJ), Microhomology-mediated End Joining (MMEJ) and recombinational repair (also known as template-assisted repair or homologous recombination repair)
Edited sentence: Homologous recombination requires the presence of an identical or nearly identical sequence to be used as a template for repair of the break.In NHEJ, DNA Ligase IV, a specialized DNA ligase that forms a complex with the cofactor XRCC4, directly joins the two ends.In the final step there is crossover by means of RecA-dependent  homologous recombination.Three mechanisms exist to repair DSBs: non-homologous end joining (NHEJ), microhomology-mediated end joining (MMEJ) and homologous recombination