 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 . 
