Making more copies of DNA from a single desired DNA is called DNA amplification or DNA proliferation. The prepared DNA has to be amplified to get enough number of copes of DNA for gene manipulation. Two methods have been followed to amplify the DNA. They are gene cloning and PCR (Polymerase Chain Reaction).
Gene cloning : Production of multiple copies of a desired DNA in vivo by constructing an rDNA and introducing it into a bacterium, is called gene cloning.
PCR (Polymerase Chain Reaction): The invitro amplification of DNA by repeated cycles of strand separation and polymerization, is called polymerase chain reaction. PCR was invented by Kary Mullis in 1985.
Gene cloning vs PCR
Gene cloning
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PCR
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| A gene amplification technique where Recombinant DNA is constructed invitro and is amplified invivo inside a bacterium. | A gene amplification technique where the DNA is amplified in vitro. No need for the construction of rDNA . |
| Restriction enzymes, DNA ligase, vector DNA and bacterial cells are required. | Taq DNA polymerase or a thermostable DNA polymerase, RNA primers and free deoxyribonucleotides are required along with DNA segment to be amplified. |
| At least a microgram quantity of DNA is required for amplification. | A nanogram of DNA is enough for amplification. |
| A restrction enzyme is required for reisolation of the amplified DNA from rDNA. | No need for reisolation or use of enzymes. |
| For getting desired DNA, amplified DNA should be screened at the final step. | No need for screening after PCR, if the DNA is pure before starting the reaction. |
| 2-4 days should be spent for an experiment. | Maximum 4 hours is enough for an experiment. |
| No need for automation. | Automation is a must. |
| Labour intensive. | No need for intensive labours. |
| Error possibility is more. | Error possibility is less. |
| The amplified DNA is put into limited number of uses. | The amplified DNA is put into many uses because of less error possibility. |
