Viral transfer of bacterial DNA. Computer artwork showing the process of transduction, whereby genetic information is transferred from one bacterium (right column) to another (left column) by a virus. A bacteriophage virus (upper left) infects the first bacterium (upper right) and harnesses its DNA (deoxyribonucleic acid) to make numerous replications of itself. All these replicant virions now contain the section of DNA (plasmid) in question (red). When each of these virions matures and goes on to infect other bacteria they pass this DNA segment on (lower left). This process is a common tool used by molecular biologists to introduce a foreign gene into a host cell's genome.