Genetic transduction by phages and chromosomal islands: The new and noncanonical.

Generalized transduction, discovered in I Salmonella i phage P22, was the first mechanism of phage-mediated gene transfer to be identified [[8]]. However, this theory turned out to be inaccurate because phages capable of generalized transduction are not known to cause the breakdown of the bacterial chromosome into phage-sized or smaller DNA fragments [[9], [10]]. Finally, to offset the predictably catastrophic effects (splitting the viral genome in two) of in situ DNA packaging, in situ theta replication creates multiple integrated genomes so that both in situ DNA packaging and phage maturation can proceed in parallel. Phage terminase initiates DNA packaging from phage pac sites (black arrows) or phage pseudo-pac sites (gray arrows). [Extracted from the article]