Genetically modified food
Genetically modified foods, also known as genetically engineered foods, or bioengineered foods are foods produced from organisms that have had changes introduced into their DNA using various methods of genetic engineering. Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits when compared to previous methods, such as selective breeding and mutation breeding.
The discovery of DNA and the improvement of genetic technology in the 20th century played a crucial role in the development of transgenic technology. In 1988, genetically modified microbial enzymes were first approved for use in food manufacture. Recombinant rennet was used in several countries in the 1990s. Commercial sale of genetically modified foods began in 1994, when Calgene first marketed its later-withdrawn Flavr Savr delayed-ripening tomato. Most food modifications have primarily focused on cash crops in high demand by farmers such as soybean, maize/corn, canola, and cotton. Genetically modified crops have been engineered for resistance to pathogens and herbicides and for better nutrient profiles. The production of golden rice in 2000 represented the first genetically modified crop developed primarily to enhance nutritional value. GM livestock have been developed, although, as of 2015, none were on the market. As of 2015, the AquAdvantage salmon was the only animal approved for commercial production, sale and consumption by the FDA. It is the first genetically modified animal to be approved for human consumption.
Genes encoded for desired features, for instance an improved nutrient level, pesticide and herbicide resistances, and the possession of therapeutic substances, are often extracted and transferred to the target organisms, providing them with enhanced survival and production capacity. These modifications can provide consumer benefits in specific aspects such as taste, appearance, or shelf life.
There is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, but that each GM food needs to be tested on a case-by-case basis before introduction. Nonetheless, members of the public are much less likely than scientists to perceive GM foods as safe. The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation, which varied due to geographical, religious, social, and other factors.
Definition
Genetically modified foods are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering as opposed to traditional cross breeding. In the U.S., the Department of Agriculture and the Food and Drug Administration favor the use of the term genetic engineering over genetic modification as being more precise; the USDA defines genetic modification to include "genetic engineering or other more traditional methods".According to the World Health Organization, "Foods produced from or using GM organisms are often referred to as GM foods."
What constitutes a genetically modified organism is not clear and varies widely between countries, international bodies and other communities, has changed significantly over time, and was subject to numerous exceptions based on "convention", such as exclusion of mutation breeding from the EU definition.
'Non-GMO' or 'GMO-free' labeling schemes in food marketing exhibit significant inconsistency. Products such as water or salt, which contain no genetic material and thus cannot be genetically modified, are sometimes labeled to create an impression of superior health benefits.
History
Human-directed genetic manipulation of food began with the domestication of plants and animals through artificial selection at about 10,500 to 10,100 BC. The process of selective breeding, in which organisms with desired traits are used to breed the next generation and organisms lacking the trait are not bred, is a precursor to the modern concept of genetic modification. With the discovery of DNA in the early 1900s and various advancements in genetic techniques through the 1970s it became possible to directly alter the DNA and genes within food.Genetically modified microbial enzymes were the first application of genetically modified organisms in food production and were approved in 1988 by the US Food and Drug Administration. In the early 1990s, recombinant chymosin was approved for use in several countries. Cheese had typically been made using the enzyme complex rennet that had been extracted from cows' stomach lining. Scientists modified bacteria to produce chymosin, which was also able to clot milk, resulting in cheese curds.
The first genetically modified food approved for release was the Flavr Savr tomato in 1994. Developed by Calgene, it was engineered to have a longer shelf life by inserting an antisense gene that delayed ripening. China was the first country to commercialize a transgenic crop in 1993 with the introduction of virus-resistant tobacco. In 1995, Bacillus thuringiensis Potato was approved for cultivation, making it the first pesticide producing crop to be approved in the US. Other genetically modified crops receiving marketing approval in 1995 were: canola with modified oil composition, Bt maize/corn, cotton resistant to the herbicide bromoxynil, Bt cotton, glyphosate-tolerant soybeans, virus-resistant squash, and another delayed ripening tomato.
With the creation of golden rice in 2000, scientists had genetically modified food to increase its nutrient value for the first time.
By 2010, 29 countries had planted commercialized biotech crops and a further 31 countries had granted regulatory approval for transgenic crops to be imported. The US was the leading country in the production of GM foods in 2011, with twenty-five GM crops having received regulatory approval. In 2015, 92% of corn, 94% of soybeans, and 94% of cotton produced in the US were genetically modified varieties.
The first genetically modified animal to be approved for food use was AquAdvantage salmon in 2015. The salmon were transformed with a growth hormone-regulating gene from a Pacific Chinook salmon and a promoter from an ocean pout enabling it to grow year-round instead of only during spring and summer.
A GM white button mushroom has been approved in the United States since 2016. See [|§Mushroom] below.
The most widely planted GMOs are designed to tolerate herbicides. The use of herbicides presents a strong selection pressure on treated weeds to gain resistance to the herbicide. Widespread planting of GM crops resistant to glyphosate has led to the use of glyphosate to control weeds and many weed species, such as Palmer amaranth, acquiring resistance to the herbicide.
In 2021, the first CRISPR-edited food has gone on public sale in Japan. Tomatoes were genetically modified for around five times the normal amount of possibly calming GABA. CRISPR was first applied in tomatoes in 2014. Shortly afterwards, the first CRISPR-gene-edited marine animal/seafood and second set of CRISPR-edited food has gone on public sale in Japan: two fish of which one species grows to twice the size of natural specimens due to disruption of leptin, which controls appetite, and the other grows to 1.2 the natural average size with the same amount of food due to disabled myostatin, which inhibits muscle growth.
Process
Creating genetically modified food is a multi-step process. The first step is to identify a useful gene from another organism that you would like to add. The gene can be taken from a cell or artificially synthesised, and then combined with other genetic elements, including a promoter and terminator region and a selectable marker. Then the genetic elements are inserted into the target's genome. DNA is generally inserted into animal cells using microinjection, where it can be injected through the cell's nuclear envelope directly into the nucleus, or through the use of viral vectors. In plants the DNA is often inserted using Agrobacterium-mediated recombination, biolistics or electroporation. As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through tissue culture. In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells. Further testing using PCR, Southern hybridization, and DNA sequencing is conducted to confirm that an organism contains the new gene.Traditionally the new genetic material was inserted randomly within the host genome. Gene targeting techniques, which creates double-stranded breaks and takes advantage on the cells natural homologous recombination repair systems, have been developed to target insertion to exact locations. Genome editing uses artificially engineered nucleases that create breaks at specific points. There are four families of engineered nucleases: meganucleases, zinc finger nucleases, transcription activator-like effector nucleases, and the Cas9-guideRNA system. TALEN and CRISPR are the two most commonly used and each has its own advantages. TALENs have greater target specificity, while CRISPR is easier to design and more efficient.
By organism
Crops
Genetically modified crops are genetically modified plants that are used in agriculture. The first crops developed were used for animal or human food and provide resistance to certain pests, diseases, environmental conditions, spoilage or chemical treatments. The second generation of crops aimed to improve the quality, often by altering the nutrient profile. Third generation genetically modified crops could be used for non-food purposes, including the production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation. GM crops have been produced to improve harvests through reducing insect pressure, increase nutrient value and tolerate different abiotic stresses. As of 2018, the commercialised crops are limited mostly to cash crops like cotton, soybean, maize/corn and canola and the vast majority of the introduced traits provide either herbicide tolerance or insect resistance.The majority of GM crops have been modified to be resistant to selected herbicides, usually a glyphosate or glufosinate based one. Genetically modified crops engineered to resist herbicides are now more available than conventionally bred resistant varieties. Most currently available genes used to engineer insect resistance come from the Bacillus thuringiensis bacterium and code for delta endotoxins. A few use the genes that encode for vegetative insecticidal proteins. The only gene commercially used to provide insect protection that does not originate from B. thuringiensis is the Cowpea trypsin inhibitor. CpTI was first approved for use in cotton in 1999 and is currently undergoing trials in rice. Less than one percent of GM crops contained other traits, which include providing virus resistance, delaying senescence and altering the plants composition.
Adoption by farmers has been rapid, between 1996 and 2013, the total surface area of land cultivated with GM crops increased by a factor of 100. Geographically though the spread has been uneven, with strong growth in the Americas and parts of Asia and little in Europe and Africa in 2013 only 10% of world cropland was GM, with the US, Canada, Brazil, and Argentina being 90% of that. Its socioeconomic spread has been more even, with approximately 54% of worldwide GM crops grown in developing countries in 2013. Although doubts have been raised, most studies have found growing GM crops to be beneficial to farmers through decreased pesticide use as well as increased crop yield and farm profit.