Bacteriophages (or phages) are viruses that infect and parasitize bacteria. These phages can transfer DNA from one bacterium to another through a process known as genetic transduction. This is thought to be the major means by which bacteria evolve and acquire the antibiotic resistance and virulence factors that accelerate the emergence of new and progressively more pathogenic strains. Up to now, two mechanisms of genetic transduction were known: generalized and specialized transduction. For over 60 years, since their discovery by American scientist and Nobel laureate Joshua Lederberg, these two mechanisms have stood as the only mechanisms of genetic transduction.