In a molecular cloning experiment, the DNA to be cloned is got from an organism of interest, then treated with enzymes in the test tube to get smaller DNA fragments. These fragments are then joined with vector DNA to produce recombinant DNA molecules. The recombinant DNA is then introduced into a host organism (typically an easy-to-grow, benign, laboratory strain of "E. coli" bacteria). This produces a population of organisms in which recombinant DNA molecules are replicated along with the host DNA. Because they contain foreign DNA fragments, these are "transgenic" or genetically-modified microorganisms (GMO). 