 The first process, non-homologous end joining (NHEJ), can join the two broken ends of DNA in the G1, S and G2 phases of interphase.The second process, homologous recombinational repair (HRR), is more accurate than NHEJ in repairing double-strand breaks.HRR is active during the S and G2 phases of interphase when DNA replication is either partially accomplished or after it is completed, since HRR requires two adjacent homologs.