Question

Compare and contrast transduction (general and specific), transformation, and transfection

Answer 1

General and specialized transduction	Transformation	Transfection
It involves use of viruses (bacteriophages) to transfer genes from one bacteria to another.	It is naturally occurring process of gene transfer. There is absorption of the genetic material by a cell via cell membrane. The foreign DNA fuses with host DNA and is expressed in the cell	Pores are created in eukaryotic cell membrane for insertion of foreign genetic material.
The lytic or lysogenic cycle of the bacteriophage is used for transduction. In lysogenic cycle, the phage remains dormant in host cell. When lytic cycle is induced by UV light, it causes release of progeny phages from the bacterial cell. In lytic cycle, the progeny phages may carry some part of the bacterial genome, which is transferred to the second bacterial cell when infected.	In artificial transformation, cold cells are placed in calcium chloride and then treated with heat shock. As a result, the cells become permeable. Electroporation is the non chemical method for artificial transformation.	Chemical such as calcium phosphate or cationic polymers or liposomes are used to create pores in cell membrane. Non chemical based gene transfer include electroporation, sonoporation, impalefection, optical transfection, nucleofection, heat shock, etc. Magnetofaction can be used to transfer foreign DNA in nanoparticles.
Transduction involves viral based transfer in bacteria.	Transformation is mainly use for bacterial cells. Plasmids are transformed in bacteria.	Transfection is exclusively in mammalian cells
Transduction is a biological method of gene transfer	Transformation can be natural (without use of chemicals, or chemical or non chemical/	Transfection involves chemical and non chemical methods.
Transduction can be generalized or specialized. In generalized transduction, any bacteria gene can be transferred between bacteria. In specialized transduction, limited or specific genes are transferred between bacteria. Generalized transduction involves lytic phages while specialized transduction involves lysogenic phages.	It can be both natural as well as artificial. . In natural transformation, the foreign DNA attaches to a receptor on host cell membrane and enters the cells with the host translocase protein. Only one strand of DNA enters the cell as the other strand is destroyed by nucleases. In artificial transformation, plasmid DNA is transferred with the help of chemical or nonchemical means.	Transfection can be transient, where in the gene is expressed in the host cell for a short period of time. In stable transfection, the DNA is maintained in the animal cells for long period.

Comparison of transduction, transformation, and transfection:

1) All three methods are used to transfer foreign genes into biological cells.

2) The host cell can acquire new genes in these processes.

3) These three methods involves integration of the foreign DNA into host genome, except in case of plasmid mediated transformation. The DNA then recombines with the host nucleic acid.