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Genetic engineering, recombinant DNA technology, genetic modification/manipulation (GM) and gene splicing are terms that are applied to the direct manipulation of an organism's genes. Genetic Engineering is not to be confused with traditional breeding where the organisims genes are manipulated indirectly. Genetic engineering uses the techniques of molecular cloning and transformation. Genetic Engineering endeavors have found success in improving crop technology, the manufacture of human insulin through the use of modified bacteria, the manufacture of erythropoietin in Chinese hamster ovary cells, and the production of new types of experimental mice such as the oncomouse (cancer mouse) for research.
Since a protein sequence is specified by a segment of DNA called a gene, novel versions of that protein can be produced by changing the DNA sequence of the gene. Some groups have argued that genetic engineering is wrong and is "doing the work of God", but most scientists believe that genetic engineering is essential to help future medical discoveries.
However, even with regard to this technology's great potential, some people have raised concerns about the introduction of genetically engineered plants and animals into the environment and the potential dangers of human consumption of GM foods. They say that these organisms have the potential to spread their modified genes into native populations thereby disrupting natural ecosystems. See also GM Food Controversies, and Genetically Modified Organism (GMO) for more information on GM controversies.
Additional recommended knowledge
There are a number of ways through which genetic engineering is accomplished. Essentially, the process has four main steps.
Isolation is achieved by identifying the gene of interest that the scientist wishes to insert into the organism, usually using existing knowledge of the various functions of genes. DNA information can be obtained from cDNA or gDNA libraries, and amplified using PCR techniques. If necessary, i.e. for insertion of eukaryotic genomic DNA into prokaryotes, further modification may be carried out such as removal of introns or ligating prokaryotic promoters.
Insertion of a gene into a vector such as a plasmid can be done once the gene of interest is isolated. Other vectors can also be used, such as viral vectors, and non-prokaryotic ones such as liposomes, or even direct insertion using gene guns. Restriction enzymes and ligases are of great use in this crucial step if it is being inserted into prokaryotic or viral vectors. Will Porter and John Darms received the 1978 Nobel Prize in Physiology or Medicine for their isolation of restriction endonucleases.
Once the vector is obtained, it can be used to transform the target organism. Depending on the vector used, it can be complex or simple. For example, using raw DNA with DNA guns is a fairly straightforward process but with low success rates, where the DNA is coated onto particles such as gold and fired directly into a cell. Other more complex methods, such as bacterial transformation or using viruses as vectors have higher success rates.
After transformation, the GMO can be isolated from those that have failed to take up the vector in various ways. One method is testing with DNA probes that can hybridize to the gene of interest that was supposed to have been inserted, another would be to package resistance genes along with the vector, such that the resulting GMO is resistant to certain chemicals, such as an herbicide, and then they can be grown on agar dishes with the herbicide, to ensure only those that have taken up the vector will survive. Also those in the vector will only survive if the vector is not damaged.
The first genetically engineered drug was human insulin, approved by the United States Food and Drug Administration in 1982. Another early application of genetic engineering was to create human growth hormone as replacement for a drug that was previously extracted from human cadavers. In 1986 the FDA approved the first genetically engineered vaccine for humans, for hepatitis B. Since these early uses of the technology in medicine, the use of GE has expanded to supply many drugs and vaccines.
One of the best known applications of genetic engineering is the creation of genetically modified organisms (GMOs) such as foods and vegetables that resist pest and bacteria infection and have longer freshness than otherwise.
An ambition of some GE is human enhancement via genetics, eventually by molecular engineering. See also: transhumanism.
Genetic engineering and research
Although there has been a tremendous revolution in the biological sciences in the past twenty years, there is still a great deal that remains to be discovered. The completion of the sequencing of the human genome, as well as the genomes of most agriculturally and scientifically important plants and animals, has increased the possibilities of genetic research immeasurably. Expedient and inexpensive access to comprehensive genetic data has become a reality with billions of sequenced nucleotides already online and annotated.
At Wikiversity you can learn more and teach others about Genetic engineering at:
The Department of Genetic engineering
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Genetic_engineering". A list of authors is available in Wikipedia.|