A genetically modified organism (GMO) or genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes. Transgenic organisms, a subset of GMOs, are organisms which have inserted DNA that originated in a different species. Some GMOs contain no DNA from other species and are therefore not transgenic but cisgenic.
Production
Further information: Horizontal Gene Transfer and Transformation (genetics)Genetic modification involves the insertion or deletion of genes. When genes are inserted, they usually come from a different species, which is a form of horizontal gene transfer. In nature this can occur when exogenous DNA penetrates the cell membrane for any reason. To do this artificially may require attaching the genes to a virus or just physically inserting the extra DNA into the nucleus of the intended host with a very small syringe, or with very small particles fired from a gene gun. However, other methods exploit natural forms of gene transfer, such as the ability of Agrobacterium to transfer genetic material to plants, or the ability of lentiviruses to transfer genes to animal cells.
History
The general principle of producing a GMO is to add new genetic material into an organism's genome. This is called genetic engineering and was made possible through the discovery of DNA and the creation of the first recombinant bacteria in 1973, i.e., E. coli expressing a Salmonella gene. This led to concerns in the scientific community about potential risks from genetic engineering, which were thoroughly discussed at the Asilomar Conference. One of the main recommendations from this meeting was that government oversight of recombinant DNA research should be established until the technology was deemed safe. Herbert Boyer then founded the first company to use recombinant DNA technology, Genentech, and in 1978 the company announced creation of an E. coli strain producing the human protein insulin.
In 1986, field tests of bacteria genetically engineered to protect plants from frost damage (ice-minus bacteria) at a small biotechnology company called Advanced Genetic Sciences of Oakland, California, were repeatedly delayed by opponents of biotechnology. In the same year, a proposed field test of a microbe genetically engineered for a pest resistance protein by Monsanto Company was dropped.
Uses
GMOs have widespread applications. They are used in biological and medical research, production of pharmaceutical drugs, experimental medicine (e.g. gene therapy), and agriculture (e.g. golden rice). The term "genetically modified organism" does not always imply, but can include, targeted insertions of genes from one species into another. For example, a gene from a jellyfish, encoding a fluorescent protein called GFP, can be physically linked and thus co-expressed with mammalian genes to identify the location of the protein encoded by the GFP-tagged gene in the mammalian cell. Such methods are useful tools for biologists in many areas of research, including those who study the mechanisms of human and other diseases or fundamental biological processes in eukaryotic or prokaryotic cells.
To date the broadest application of GMO technology is patent-protected food crops which are resistant to commercial herbicides or are able to produce pesticidal proteins from within the plant, or stacked trait seeds, which do both. The largest share of the GMO crops planted globally are owned by Monsanto Company, according to the company. In 2007, Monsanto’s trait technologies were planted on 246 million acres (1,000,000 km 2 ) throughout the world, a growth of 13 percent from 2006.
In the corn market, Monsanto’s triple-stack corn – which combines Roundup Ready 2 weed control technology with YieldGard Corn Borer and YieldGard Rootworm insect control – is the market leader in the United States. U.S. corn farmers planted more than 17 million acres (69,000 km 2 ) of triple-stack corn in 2007, and it is estimated the product could be planted on 45 million to 50 million acres (200,000 km 2 ) by 2010. In the cotton market, Bollgard II with Roundup Ready Flex was planted on nearly 3 million acres (12,000 km 2 ) of U.S. cotton in 2007.
According to the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), of the approximately 8.5 million farmers who grew biotech crops in 2005, some 90% were resource-poor farmers in developing countries. These include some 6.4 million farmers in the cotton-growing areas of China, an estimated 1 million small farmers in India, subsistence farmers in the Makhathini flats in KwaZulu Natal province in South Africa, more than 50,000 in the Philippines and in seven other developing countries where biotech crops were planted in 2005. ISAAA estimated that by 2008, 13.3 million farmers were growing GM crops, including 12.3 million in developing counties,. These comprised 7.1 million in China (Bt cotton), 5.0 million in India (Bt cotton), and 200,000 in the Philippines.
"The Global Diffusion of Plant Biotechnology: International Adoption and Research in 2004", a study by Dr. Ford Runge of the University of Minnesota, estimates the global commercial value of biotech crops grown in the 2003–2004 crop year at US$44 billion.
In the United States the United States Department of Agriculture (USDA) reports on the total area of GMO varieties planted. According to National Agricultural Statistics Service, the States published in these tables represent 81-86 percent of all corn planted area, 88-90 percent of all soybean planted area, and 81-93 percent of all upland cotton planted area (depending on the year).
USDA does not collect data for global area. Estimates are produced by the International Service for the Acquisition of Agri-biotech Applications (ISAAA) and can be found in the report, Global Status of Commercialized Transgenic Crops: 2007.
Transgenic animals are also becoming useful commercially. On 6 February 2009 the U.S. Food and Drug Administration approved the first human biological drug produced from such an animal, a goat. The drug, ATryn, is an anticoagulant which reduces the probability of blood clots during surgery or childbirth. It is extracted from the goat's milk.
Detection
Testing on GMOs in food and feed is routinely done by molecular techniques like DNA microarrays or qPCR. The test can be based on screening elements (like p35S, tNos, pat, or bar) or event-specific markers for the official GMOs (like Mon810, Bt11, or GT73). The array-based method combines multiplex PCR and array technology to screen samples for different potential GMOs, combining different approaches (screening elements, plant-specific markers, and event-specific markers). The qPCR is used to detect specific GMO events by usage of specific primers for screening elements or event-specific markers.
To avoid any kind of false positive or false negative testing outcome, comprehensive controls for every step of the process is mandatory. A CaMV check is important to avoid false positive outcomes based on virus contamination of the sample.
Transgenic microbes
Bacteria were the first organisms to be modified in the laboratory, due to their simple genetics. These organisms are now used for several purposes, and are particularly important in producing large amounts of pure human proteins for use in medicine.
Genetically modified bacteria are used to produce the protein insulin to treat diabetes. Similar bacteria have been used to produce clotting factors to treat haemophilia, and human growth hormone to treat various forms of dwarfism.
Transgenic animals
Transgenic animals are used as experimental models to perform phenotypic and for testing in biomedical research. Other applications include the production of human hormones such as insulin.
Fruit flies
In biological research, transgenic fruit flies ( Drosophila melanogaster ) are model organisms used to study the effects of genetic changes on development. Fruit flies are often preferred over other animals due to their short life cycle, low maintenance requirements, and relatively simple genome compared to many vertebrates.
Mammals
Genetically modified mammals are an important category of genetically modified organisms. Transgenic mice are often used to study cellular and tissue-specific responses to disease.
In 2009, scientists in Japan announced that they had successfully transferred a gene into a primate species (marmosets) and produced a stable line of breeding transgenic primates for the first time.
Cnidarians
Cnidarians such as Hydra have become attractive model organisms to study the evolution of immunity. For analytical purposes an important technical breakthrough was the development of a transgenic procedure for generation of stably transgenic hydras by embryo microinjection
Transgenic Definition | Definition of Transgenic at Dictionary.com
Function: adjective: being or used to produce an organism orcell of one species into which one or more genes of other species have been incorporated transgenic mice>transgenic corn ...
Transgenic organisms
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Genetically modified organism - Wikipedia, the free encyclopedia
A genetically modified organism (GMO) or genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques.
Transgenesis - Wikipedia, the free encyclopedia
Transgenic organisms are able to express foreign genes because the genetic code is similar for all organisms. This means that a specific DNA sequence will code for the same protein ...
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ge·net·i·cal·ly modified organism (j-n t-k-l) n. Abbr. GMO. An organism whose genetic characteristics have been altered by the insertion of a modified gene or a gene from ...
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ge·net·i·cal·ly modified organism (j-n t-k-l) n. Abbr. GMO. An organism whose genetic characteristics have been altered by the insertion of a modified gene or a gene from ...
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transgenic organism [tranz′jen·ik ′ȯr·gə‚niz·əm] (genetics) An organism into whose genome a gene or genes from another organism has been experimentally transferred and ...
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Transgenic Organisms. Information about Transgenic Organisms; Roslin Institute in Scotland (home of Dolly, the cloned sheep) Return to List of Links