Answer:
during cell division (meiosis)
Step-by-step explanation:
During meiosis, DNA double-strand breaks (DSBs) between homologous chromosomes are induced and, after the exchange of DNA pieces, breaks are jointed by specific DNA-repair enzymes (such as DNA glycosylases). DSBs can be repaired by two different mechanisms: non-homologous end-joining (NHEJ) and homologous recombination (HR), which have different functional consequences. These mechanisms of recombination have potential for increasing the genetic variation since the resulting gametes will contain a different set of chromosome fragments.