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Recombinant DNA Technology, The technology used for producing artificial DNA through the combination of, different genetic materials (DNA) from different sources is referred to, as Recombinant DNA Technology. Recombinant DNA technology is popularly, known as genetic engineering. The recombinant DNA technology emerged, with the discovery of restriction enzymes in the year 1968 by Swiss, microbiologist Werner Arber,, Inserting the desired gene into the genome of the host is not as easy as it, sounds. It 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. Thus the recombinant DNA has to be, introduced into the host. And at last, it has to be maintained in the host and, carried forward to the offspring., , Tools Of Recombinant DNA Technology, The enzymes which include the restriction enzymes help to cut, the, polymerases- help to synthesize and the ligases- help to bind. 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. They, are two types, namely Endonucleases and Exonucleases.The Endonucleases, cut within the DNA strand whereas the Exonucleases remove the nucleotides, from the ends of the strands. The restriction endonucleases are sequencespecific which are 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. This gives rise to sticky ends in the sequence. 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.The vectors – help in carrying and, integrating the desired gene. These form a very important part of the tools of, recombinant DNA technology as they are the ultimate vehicles that carry, forward the desired gene into the host organism. Plasmids and bacteriophages, are the most common vectors in recombinant DNA technology that are used as, they have a very high copy number. The vectors are made up of an origin of, replication- This is a sequence of nucleotide from where the replication starts,, a selectable marker – constitute genes which show resistance to certain, antibiotics like ampicillin; and cloning sites – the sites recognized by the, restriction enzymes where desired DNAs are inserted.Host organism – into

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which the recombinant DNA is introduced. 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.There are a number of ways in which, these recombinant DNAs are inserted into the host, namely – microinjection,, biolistics or gene gun, alternate cooling and heating, use of calcium ions, etc.