Recombinant DNA

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Recombinant DNA (rDNA) is an artificial DNA sequence resulting from the combination of different DNA sequences. The name comes from the process, which "recombines" DNA from two or more disparate sources. A recombinant protein is a protein produced by an organism after the relevant DNA is inserted into its genome (that is, by a genetically modified organism).

Recombinant DNA technique was discovered by Stanley Norman Cohen and Herbert Boyer in 1973. They published their findings in November 1973 in the paper “Construction of Biologically Functional Bacterial Plasmids in vitro”, which described a technique to isolate and amplify genes, or DNA segments, and insert them into another cell with precision creating a Transgenic Bacteria. Recombinant DNA technology was made possible by the discovery of restriction endonucleases by Werner Arber, Daniel Nathans, and Hamilton Smith, for which they received the 1978 Nobel Prize in Medicine.

The term recombinant DNA refers to a new combination of DNA molecules that are not found together naturally. Although processes such as crossing over (genetic recombination) technically produce recombinant DNA, the term is generally reserved for DNA produced by artificially joining molecules derived from different biological sources.

1 Uses
2 Plasmids and recombinant DNA technology
3 See also
4 References
5 External links

[edit] Uses

Recombinant DNA is used for genetic transformation to produce genetically modified organisms. Some examples of recombinant DNA products are peptide hormone medications including insulin, growth hormone, and oxytocin. Vaccines can also be produced using recombinant processes (as is the case with the Hep. B vaccine). The organism most commonly used is Escherichia coli.

[edit] Plasmids and recombinant DNA technology

Plasmids are extrachromosomal fragments of DNA present in some bacteria. A plasmid can transfer genetic material to another bacterium, allowing it to express the transmitted gene(s). Restriction enzymes which cut sequences of DNA at certain spots are used to splice into a plasmid the DNA sequence for the desired gene. The plasmid is then inserted into a bacterium in order to express the gene and produce the protein coded for by the gene. Large amounts of the protein can be produced in a factory with vats of the genetically engineered bacteria. A plasmid is extrachromosomal self replicating circular DNA. Most of the plasmid is used for the production of antibiotics.

Most eukaryotes do not maintain canonical plasmids; yeast is a notable exception.^[1] In addition, the Ti plasmid of the bacterium Agrobacterium tumefaciens can be used to integrate foreign DNA into the genomes of many plants. Other methods of introducing or creating recombinant DNA in eukaryotes include site-specific recombination and transfection with modified viruses.