Genetic recombination is the process of exchanging genetic material between different organisms or between different regions of the same chromosome, leading to the production of offspring with combinations of traits that differ from those found in either parent. This process creates genetic diversity at the level of genes that reflects differences in the DNA sequences of different organisms. Genetic recombination occurs naturally in meiosis, the process of cell division that occurs in eukaryotes to produce offspring. During meiosis, homologous pairs of maternal and paternal chromosomes align, and the arms of the chromosomes can overlap and temporarily fuse, causing a crossover. Crossovers result in recombination and the exchange of genetic material between the maternal and paternal chromosomes, resulting in offspring with different combinations of genes than their parents. Genetic recombination also occurs in bacteria and archaea, which use asexual reproduction, and can be artificially induced in laboratory settings, producing recombinant DNA for purposes including vaccine development. In genetic engineering, recombination can refer to the artificial and deliberate recombination of disparate pieces of DNA, often from different organisms, creating what is called recombinant DNA.