Recombinant DNA technology is a technique which changes the phenotype of an organism (host) when a genetically altered vector is introduced and integrated into the genome of the organism. So, basically, the process involves introducing a foreign piece of DNA into the genome which contains our gene of interest. This gene which is introduced is the recombinant gene and the technique is called the recombinant DNA technology. Embedding the desired gene into the genome of the host is not as simple as it sounds. Developing a recombinant DNA involves a series of sequential steps which are discussed below.
Process of Recombinant DNA Technology
Recombinant DNA technology involves the selection of the desired gene for administration into the host followed by a selection of the perfect vector with which the gene has to be integrated and recombinant DNA formed. This recombinant DNA then has to be introduced into the host. And at last, it has to be maintained in the host and carried forward to the offsprings. Let’s go through each step in detail.
Isolation of DNA:
Being a nucleic acid enclosed within the nucleus, isolation of DNA is not an easy task. Isolation of DNA is an enzymatically controlled process where the plant or animal cells are treated with certain enzymes. Enzymes such as lysozyme (bacteria), cellulase (plant cells), and chitinase (fungus) are different enzymes used to isolate a pure DNA from the cells.
Fragmentation of DNA:
The isolated and purified DNA is treated with restriction endonucleases which cut the DNA into fragments. The restriction enzymes used in recombinant DNA technology play a major role in determining the location at which the desired gene is inserted into the vector genome. The restriction endonucleases are sequence-specific which is usually palindrome sequences and cut the DNA at specific points. They scrutinize the length of DNA and make the cut at the specific site called the restriction site. The desired genes and the vectors are cut by the same restriction enzymes to obtain the complementary sticky notes, thus making the work of the ligases easy to bind the desired gene to the vector.
Amplification of Gene of Interest:
Polymerase chain reaction (PCR) is a process to amplify the gene once the proper gene of interest has been cut using the restriction enzymes. Through this process, multiple copies of the gene of interest can be produced. PCR proceeds in three stages, denaturation, annealing and extension.
Insertion of recombinant DNA into the host:
The host is the ultimate tool of recombinant DNA technology which takes in the vector engineered with the desired DNA with the help of the enzymes. Insertion of the desired recombinant DNA into the host organism can be achieved in various ways. This includes– microinjection, biolistics or the gene gun, alternate cooling and heating, use of calcium ions, etc. The successfully transformed cells/organisms carry forward the recombinant gene to the off-springs.
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