Generalized and Specialized Transduction
There are several mechanisms in which bacteria transfer genes with one another. Vertical gene transfer is the transfer of genetic material during cell division. Horizontal gene transfer, on the other hand, is the transfer of genetic material between different species of bacteria; three types are found. Conjugation is the transfer of DNA by direct contact with the cell. Transformation is the uptake of genetic material from the surrounding. Transduction is the transfer of genes via bacterophages. Two kinds of bacterial transductions can be found: generalized and specialized.
Viruses are unable to replicate on their own. To do so, they infect a cell and force it to make copies of itself. In the case of generalized transduction, a virulent phage infects the bacterial cell by attaching to a receptor area and injecting its nucleic acid into the cell. The host DNA is broken into smaller fragments, replicated and translated. When phages are assembled, they occasionally carry a piece of the bacterial DNA picked at random. Any segment of the bacterial DNA can be assembled in the new phage. The cell then enters the lytic phase, releasing the phage. This phage then infects another cell, transferring the bacterial DNA which recombines with the host’s chromosome.
In specialized transduction, only a few specific genes are transferred from one bacterial cell to another and it requires a certain type of phage, called temperate bacteriophage. When it infects the cell, its DNA enters the cell and binds to a specific site on the host chromosome, producing a lysogenic cycle. This integrated DNA can remain for long periods of time without harming the bacterial cell. Under certain conditions, including UV radiation, the prophage can be excised from the host chromosome and the lytic cycle begins. A piece of the phage DNA is left in the bacterial