Homologous recombination is a type of
genetic recombination in which
nucleotide sequences are exchanged between two similar or identical molecules of
DNA. It is most widely used by cells to accurately
repair harmful breaks that occur on both strands of DNA, known as double-strand breaks. Homologous recombination also produces new combinations of DNA sequences during
meiosis, the process by which
eukaryotes make
gamete cells, like
sperm and
egg cells in animals. These new combinations of DNA represent
genetic variation in offspring, which in turn enables populations to
adapt during the course of
evolution. Homologous recombination is also used in
horizontal gene transfer to exchange genetic material between different strains and species of bacteria and
viruses.