 Homologous recombination is an important method of integrating donor DNA into a recipient organism 's genome in horizontal gene transfer , the process by which an organism incorporates foreign DNA from another organism without being the offspring of that organism . Homologous recombination requires incoming DNA to be highly similar to the recipient genome , and so horizontal gene transfer is usually limited to similar bacteria . Studies in several species of bacteria have established that there is a log @-@ linear decrease in recombination frequency with increasing difference in sequence between host and recipient DNA . 
