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Genetic engineering

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File:Glowing tobacco plant.jpg
An iconic image of genetic engineering; this "autoluminograph" from 1986 of a glowing transgenic tobacco plant bearing the luciferase gene, illustrating the possibilities of genetic engineering.

Genetic engineering, recombinant DNA technology, genetic modification/manipulation (GM) and gene splicing are terms that are applied to the manipulation of genes, generally implying that the process is outside the organism's natural reproductive process. It involves the isolation, manipulation and reintroduction of DNA into cells or model organisms, usually to express a protein. The aim is to introduce new characteristics or attributes physiologically or physically, such as making a crop resistant to a herbicide, introducing a novel trait, enhancing existing ones, or producing a new protein or enzyme. Successful endeavours include 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. There are a number of ways through which this could be achieved. After isolating a section of DNA that includes the gene, the gene or required portion of the gene is cut out. After modification of the sequence if necessary, it may be introduced (spliced) into a different DNA segment or into a vector for transformation into living cells. Daniel Nathans and Hamilton Smith received the 1978 Nobel Prize in Physiology or Medicine for their isolation of restriction endonucleases, which are able to cut DNA at specific sites. Together with ligase, which can join fragments of DNA together, restriction enzymes formed the initial basis of recombinant DNA technology. Some groups have argued[citation needed] 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[citation needed]. Professor Stephen Hawkings defended the genetic enhancing of our species in order to compete with Artificial intelligence.[1]

At Wikiversity, you can learn more and teach others about Genetic engineering at the Department of Genetic engineering

Processes

There are many variations and complications involved in genetically manipulation. These lead to variation in the process of changing the genetic code. However, there are two main processes that are in wide use in altering the DNA code, and one recognised process that adds in a gene into an organism that does not contain it. Above is a brief outline of the means of adding a gene into DNA. However, it is more complicated than shown. The aim is to introduce a new gene into the DNA of an organism. This gene will hold the code for producing a certain protein. To start the process, the required protein must be identified and analysed to ascertain the sequence of amino acids that make up the primary structure of the protein. each codon from a gene contains 3 bases and codes for an amino acid. There are twenty human made amino acids so some codons code for the same amino acid. These codons can be found by using known data that shows which codon codes for which amino acid. The corresponding codon can then be put in the correct place so that it can replicate the function of the original gene codon. Once all the codons have been found and they have been placed in the correct order, the complete gene can be created. Once this is done, it is replicated using polimerase chain reactionor PCR. Once this has been completed, the above mentioned restriction enzymes cut a gap in the required place in the host DNA and the millions of replicated artificial genes can be inserted into the host.

Applications

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).

There are potentially momentous biotechnological applications of GM, for example oral vaccines produced naturally in fruit, at very low cost.

A radical ambition of some groups is human enhancement via genetics, eventually by molecular engineering. See also: transhumanism.

Genetic engineering and research

Although there has been a tremendous[1] 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.

Now that the rapid sequencing of arbitrarily large genomes has become a simple, if not trivial affair, a much greater challenge will be elucidating function of the extraordinarily complex web of interacting proteins, dubbed the proteome, that constitutes and powers all living things. Genetic modification permits alteration of the primary structure of proteins and has therefore become a powerful tool in analyzing structure-function relationships in protein research. The use of the term "genetic engineering" to describe the experimental genetic modification of whole organisms, however, suggests a level of precision and an understanding of developmental biological principles beyond what has been achieved. Nonetheless, research progress has been made using a wide variety of techniques, including:

  • Loss of function, such as in a knockout experiment, in which an organism is engineered to lack the activity of one or more genes. This allows the experimenter to analyze the defects caused by this mutation, and can be considerably useful in unearthing the function of a gene. It is used especially frequently in developmental biology. A knockout experiment involves the creation and manipulation of a DNA construct in vitro, which, in a simple knockout, consists of a copy of the desired gene which has been slightly altered such as to cripple its function. The construct is then taken up by embryonic stem cells, where the engineered copy of the gene replaces the organism's own gene. These stem cells are injected into blastocysts, which are implanted into surrogate mothers. Another method, useful in organisms such as Drosophila (fruit fly), is to induce mutations in a large population and then screen the progeny for the desired mutation. A similar process can be used in both plants and prokaryotes.
  • Gain of function experiments, the logical counterpart of knockouts. These are sometimes performed in conjunction with knockout experiments to more finely establish the function of the desired gene. The process is much the same as that in knockout engineering, except that the construct is designed to increase the function of the gene, usually by providing extra copies of the gene or inducing synthesis of the protein more frequently.
  • 'Tracking' experiments, which seek to gain information about the localization and interaction of the desired protein. One way to do this is to replace the wild-type gene with a 'fusion' gene, which is a juxtaposition of the wild-type gene with a reporting element such as Green Fluorescent Protein (GFP) that will allow easy visualization of the products of the genetic modification. While this is a useful technique, the manipulation can destroy the function of the gene, creating secondary effects and possibly calling into question the results of the experiment. More sophisticated techniques are now in development that can track protein products without mitigating their function, such as the addition of small sequences which will serve as binding motifs to monoclonal antibodies.
  • Expression studies aim to discover where and when specific proteins are produced. In these experiments the DNA sequence before the DNA that codes for a protein, known as a gene's promoter is reintroduced into an organism with the protein coding region replaced by a reporter gene such as GFP or an enzyme that catalyzes the production of a dye. Thus the time and place where a particular protein is produced can be observed. Expression studies can be taken a step further by altering the promoter to find which pieces are crucial for the proper expression of the gene and are actually bound by transcription factor proteins; this process is known as promoter bashing.


Pros and Cons: 

Genetic engineering of the human food supply is a highly contentious issue, with
 credentialed scientists arguing on each side. Most likely the controversy will continue. The
 effort by biotech companies to genetically modify food will continue to increase and
 resistance by consumers to genetically modified food will continue to grow.

 Overview

 PRO: Genetic engineering is a valuable new technology that can develop more plentiful and
 nutritious foods, with great potential benefits for humanity and the environment, and this
 new scientific discovery needs to be implemented as quickly as possible for humanitarian
 reasons.

 CON: As with every new scientific technology, harmful side effects of genetic engineering
 are inevitable and great care should be taken in its implementation, including carefully
 controlled long-term tests on human health and environmental impacts. 

 Natural Or Unnatural?

 PRO: Genetic engineering is a natural extension of traditional breeding; just as
 conventional breeding allows us to combine valuable traits within closely related species,
 genetic engineering allows scientists to access genes from a broader range of organisms to
 produce more valuable and productive crops and livestock.

 CON: Genetic engineering uses artificial laboratory techniques, rather than natural
 reproductive mechanisms, techniques which breach natural reproductive barriers and
 combine genes from distant species in ways that could never occur in nature -- suddenly
 altering genetic patterns that have developed over millions of years, and greatly increasing
 the likelihood of unanticipated side effects.

 Is The Process Precise?

 PRO: While natural breeding is an imprecise and uncontrolled combination of thousands
 of genes, genetic engineering is a precise technological process that allows scientists to first
 select the specific gene desired and then use "gene guns" and other techniques to insert that
 gene in the target organism precisely. 

 CON: The choice of which gene to insert is indeed precise. But the insertion of this gene
 into a living cell is highly imprecise, with no control over where in the DNA the new gene is
 inserted. This unnatural process can disrupt the natural genetic information encoded in the
 DNA, as well as the regulation of gene expression, in ways that are uncontrolled and
 unpredictable. 

 Have Tests Been Conducted?

 PRO: All genetically engineered foods have been thoroughly tested and demonstrated to be
 safe before they are released into the marketplace.

 CON: This testing is typically conducted only on rats and other animals, by the companies
 involved. Very little of this research has been reviewed by independent scientists and then
 published in scientific journals, and the FDA does not review the research methodology.
 Such a process is considered only preliminary with, for example, food additives and
 pharmaceutical drugs.

 Is Human Testing Needed?

 PRO: Genetically engineered foods are usually "substantially equivalent" to other foods,
 with no increased risk to human health, and no need for the lengthy and expensive human
 testing demanded of, for example, new food additives.

 CON: The unpredictable disruptions in normal DNA functioning caused by genetic
 engineering can produce unanticipated and unknown side effects for human health,
 including unknown and unpredictable toxins and allergens, and these possibilities can
 only be definitively assessed through human testing.

 Is Safety Demonstrated?

 PRO: Genetically engineered foods have been sold in the United States for several years and
 there is no evidence to indicate that these foods have harmed human health in any way.

 CON: There is also no evidence that genetically engineered foods are safe for human health.
 The reason is the same in both cases: no human studies have been conducted. There is no
 objective way to determine if any of these foods have long-term effects that negatively
 impact human health.

 Can We Eat Pesticide Foods Safely?

 PRO: Certain genetically engineered potatoes and corn produce their own Bt, a pesticide
 that protects the crop from insects, thus decreasing costs and increasing yield with no
 negative impact on human health. 

 CON: These foods are regulated as pesticides by the EPA. When Bt is sold as a pesticide,
 people are warned not to swallow it, breathe it, or get it in cuts. Yet potatoes and corn that
 produce their own Bt are sold with no human testing.

 The Future Of Organics

 PRO: If people do not wish to eat genetically engineered foods then they have an option
 now; they can eat organic foods which, according to rules released by the United States
 Department of Agriculture, must be free of all genetic engineering.

 CON: Genetic engineering itself damages organic farming; genetically engineered corn, for
 example, outcrosses with organic corn in nearby fields and contaminates the crop;
 genetically engineered corn and potatoes containing the Bt toxin will produce insects
 resistant to Bt, making Bt spray ineffective for organic farmers.

 Environmental Impacts

 PRO: The use of genetic engineering in agriculture will increase crop productivity, thereby
 reducing the demand for agricultural land, while it will also reduce the use of herbicides
 and pesticides, thereby reducing the damage done to the environment through modern
 agrichemical farming technologies.

 CON: Several studies have been done, and there is little evidence to show that genetic
 engineering increases crop yield or reduces herbicide and pesticide use. Meanwhile,
 research has shown that genes for resistance to herbicides will outcross into the natural
 ecosystem, generating "super weeds," and that plants engineered to be pesticides will create
 resistant insect pests -- self-defeating processes that will irreversibly damage the
 environment. Moreover, no genetically modified food has yet been subject to an
 environmental impact study.

 Science vs. Culture

 PRO: Genetic engineering is a scientific and technological process, and its evaluation and
 governmental regulation should be based on purely scientific and objective criteria.

 CON: To have a purely scientific evaluation of genetically engineered foods, we need more
 science, especially human studies and environmental studies. Moreover, purely scientific
 assessment of genetic engineering ignores the fact that, for many people, food has cultural,
 ethical and religious dimensions that must also be considered. 

 Patenting DNA

 PRO: Genetic engineering produces specific and identifiable changes in the genome of
 living organisms which can be protected through patent, and this protection of intellectual
 property within the DNA (the "software" of living organisms) is fueling the rapid
 development of new and better food sources.

 CON: Historically, farmers have created the world's crop varieties through natural
 breeding. To allow large corporations to use small genetic changes to take control of these
 collectively produced resources, as well as the evolutionary process itself, is to risk that
 these corporations will take control of agricultural output worldwide. Indeed, if a few large
 biotech businesses in Western nations have control of the seed used around the world,
 serious questions will arise about the independence and national sovereignty of all other
 nations.

 Equivalence Or Choice?

 PRO: Since genetically engineered foods released into the marketplace are "substantially
 equivalent" to conventional foods, with no significant difference in taste, usability or
 commonly measured nutritional components, they need not be labeled. 

 CON: For a variety of reasons, including concerns about health testing, the environment,
 and religious and ethical values, genetically engineered food should be labeled as such,
 giving consumers a choice as to whether they wish to eat these foods and support their
 underlying values.

 Should There Be Labels?

 PRO: Most people can't tell the difference between conventional and genetically engineered
 foods, and given a choice, they will buy what is least expensive.

 CON: In nearly every country where polls have been taken, large majorities say they want
 genetically engineered foods to be labeled, so informed choices can be made.

Reading list

  • British Medical Association (1999). The Impact of Genetic Modification on Agriculture, Food and Health. BMJ Books. ISBN 0-7279-1431-6.
  • Donnellan, Craig (2004). Genetic Modification (Issues). Independence Educational Publishers. ISBN 1-86168-288-3.
  • Morgan, Sally (2003). Superfoods: Genetic Modification of Foods (Science at the Edge). Heinemann. ISBN 1-4034-4123-5.
  • Smiley, Sophie (2005). Genetic Modification: Study Guide (Exploring the Issues). Independence Educational Publishers. ISBN 1-86168-307-3.
  • Zaid, A (2001). Glossary of Biotechnology for Food and Agriculture - A Revised and Augmented Edition of the Glossary of Biotechnology and Genetic Engineering. Available in English, French, Spanish and Arabic. Rome, Italy: FAO. ISBN 92-5-104683-2. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

References

  1. ^ apud Computerworld.com.au interview with Vernor Vinge - AI will surpass human intelligence after 2020

See also

General

News

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