DNA cloning is a molecular biology technique which is used for the creation of exact replicas or clones of a particular gene or DNA using genetic engineering techniques. The DNA comprising of the target gene(s) is fragmented using restriction enzymes. The cloning is used for making numerous identical copies of a piece of DNA, such as a gene.
A clone is an organism having an exact genetic copy i.e. every single bit of their DNA is identical. Dolly was the first mammal sheep to have been cloned successfully in the year 1996.
A process of producing multiple and identical copies of a particular section of DNA is called as DNA cloning. During this technique, the selected DNA fragment is inserted into a plasmid (the circular piece of DNA) using enzymes. The enzymes used in this process are called as restriction enzymes and DNA ligase enzymes. These restriction enzymes, naturally found in bacteria are used to cut the DNA fragments at specific sequences and DNA ligase enzymes are used to paste or re-join the DNA fragments with complementary ends. The produced molecule of recombinant DNA is introduced into a selected and grown up bacteria. These bacteria reproduce by producing an exact copy of the plasmid and transferring it to their progeny, making copies of the DNA it contains.
Importance of DNA cloning
The DNA molecules produced through the cloning techniques are used for many purposes which includes:
- There is need of more DNA copies for studying about the different gene, its functions, the cause of different diseases and for other research and experiments.
- Cloning livestock, and for reviving endangered or extinct species.
- Gene therapy used to treat some genetic disorders and replacement of a particular gene.
- In pharmaceuticals industries for the production of recombinant protein to produce human proteins with biomedical applications. For example:
- The gene from the human insulin is expressed into the E. coli bacteria in order to produce the insulin hormone which is used by diabetics.
- Human growth hormone is used to treat those patients who are unable to synthesize the growth hormone naturally.
- Tissue plasminogen activator is used both in preventing blood clots and treating strokes.
- Gene cloning in agriculture:
- Crop breeding by facilitating the direct changes to the genotype of a plant.
- Altering the characteristics of a plant by providing it with one or more new genes.
- By inactivating one or more of the plant’s existing genes rather than removing them.
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