What are genetically modified crops & their food safety?

G.M. crops stand for Genetically Modified crops, derived from or produced by GM organisms have been altered through genetic, does not include forms of genetic modification such as selective breeding and mutation breeding. They are modified by taking a gene from another cell type and adapting it into the GM organism DNA, also known as the recombinant method or genetic engineering. GE crops are produced using laboratory techniques where genetic material from the cells of one species is transferred into another species to artificially create new living organisms that would never naturally occur through breeding.

According to World Health Organisation WHO -Genetically modified organisms (GMOs/GM Crops) as organisms/crops in which the genetic material (DNA) has been altered in a way that does not occur naturally.

Genetically modified crops (GM crops) are crops which have had their DNA altered in a way that does not occur naturally. Individual genes which promote durability or nutritional value are transferred from one organism to another to create biologically robust plants. Initially developed in response to growing concern about protecting crops from insects, unusual weather patterns, and harmful pesticides, GM crops are becoming more and more mainstream, dividing public opinion about the health and environmental impacts of producing and consuming crops produced in a lab. There are some benefits of GM crops: Increased resistance to pest and diseases, higher yield, better nutritional content and increased resistance to abiotic stresses such as drought, salt etc. The Organisation for Economic Co-operation and Development (OECD) defines food safety as “reasonable certainty that no harm will result from intended uses under anticipated conditions of consumption. It is often stated that GM products pose no new food safety risks when compared to traditionally produced foods, and to date, no safety problems have been identified for GM products approved for use.

Scientists first discovered that DNA naturally transfers between organisms in 1946. It is now known that there are several natural mechanisms for the flow of genes, or (horizontal gene transfer) and that these occur in nature on a large scale- for example, it is a major mechanism for antibiotic resistance in pathogenic bacteria, and it occurs between plant species. This is facilitated by transposons, retrotransposons, proviruses and other mobile genetic elements that naturally translocate to new sites in a genome. They often move to new species over an evolutionary time scale and play a major role in dynamic changes to chromosomes during evolution.

The introduction of foreign germplasm into crops has been achieved by traditional crop breeders by artificially overcoming fertility barriers. A hybrid cereal was created in 1875, by crossing wheat and rye. Since then important traits have been introduced into wheat, including dwarfing genes and rust resistance. Plant tissue culture and the induction of mutations have also enabled humans to artificially alter the makeup of plant genomes.

Transgenic plants have genes inserted into them that are derived from another species. The inserted genes can come from species within the same kingdom (plant to plant) or between kingdoms (for example, bacteria to plant). In many cases, the inserted DNA has to be modified slightly in order to correctly and efficiently express in the host organism. Transgenic carrots have been used to produce the drug Taliglucerase alfa which is used to treat Gaucher’s disease. In the laboratory, transgenic plants have been modified to increase their photosynthesis (currently about 2% at most plants to the theoretic potential of 9-10%). This is possible by changing the rubisco enzyme carboxysome, by adding CO2 pumps in the cell wall, by changing the leaf form/size. Still, other transgenic plants have been modified to fixate ambient nitrogen in the plant. Cisgenic plants are made using genes found within the same species or a closely related one, where conventional plant breeding can occur.


GM-Crops -distribution- Wold Wide [resource-http://www.itmonline.org/]

History of the Genetically modified crops

The first genetically modified plant was produced in 1982, using an antibiotic-resistant tobacco plant. The first field trials of genetically engineered plants occurred in France and the USA in 1986, when tobacco plants were engineered to be resistant to herbicides. In 1987, Plant Genetic Systems (Ghent, Belgium), founded by Marc Van Montagu and Jeff Schell, was the first company to develop genetically engineered (tobacco) plants with insect tolerance by expressing genes encoding for insecticidal proteins from Bacillus thuringiensis (Bt). The people’s Republic of China was the first country to allow commercialized transgenic plants, introducing a virus-resistant tobacco in 1992. The first genetically modified crop approval for sale in the U.S., in 1994, was the FlavrSavr tomato, which had a longer shelf life. In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil, making it the first commercially genetically engineered crop marketed in Europe. In 1995, Bt Potato was approved safe by the Environmental Protection Agency, making it the first pesticide producing crop to be approved in the USA. The following transgenic crops also received marketing approval in the US in 1995: canola with modified oil composition (calgene), Bacillus thuringiensis (Bt) Corn/maize (Ciba-Geigy), cotton resistant to the herbicide bromoxynil (Calgene), Bt cotton (Monsanto), soybeans resistant to the herbicide glyphosate (Monsanto), virus-resistant squash (Asgrow), and additional delayed ripening tomatoes (DNAP, Zeneca/Peto, and Monsanto). As of mid-1996, a total of 35 approvals had been granted to commercially grow 8 transgenic crops and one flower crop of carnations, with 8 different traits in 6 countries plus the EU. In 2000, with the production of golden rice, scientists genetically modified food to increase its nutrient value for the first time.

Methods of delivering DNA into plant cells include – Biological method or vector-mediated gene transfer – Through Agrobacterium, Other bacteria, Viruses. Physical method or direct gene transfer – Particle bombardment, Electroporation, Silicon carbide whiskers, Carbon nanofibers, The microinjection method uses a fine needle to inject a solution of DNA into a developing embryo.

Examples of Genetically modified (GM crops)

Currently, there are a number of food species for which a genetically modified version is being commercially grown. Most GM foods on the market are plant products that have been genetically modified.

Alfalfa – Resistance to glyphosate of glufosinate herbicides

Canola / Rapeseed – Resistance to herbicides (glyphosate or glufosinate), high laurate canola, Oleic acid canola

Corn, field (Maize) – Resistance to glyphosate of glufosinate herbicides. Insect resistance via producing Bt proteins, some previously used as pesticides in organic crop production. Added enzyme, alpha amylase, that converts starch into sugar to facilitate ethanol production.

Cotton (cottonseed oil) – Kills susceptible insects pests

Papaya (Hawaiian) – Resistance to the papaya ringspot virus

Rice – Golden Rice: genetically modified to contain beta-carotene (a source of vitamin A)

Soybeans – Resistance to glyphosate (see Roundup Ready soybean) or glufosinate herbicides; make less saturated fats; [103] kills susceptible insect

Pest Squash – Resistance to watermelon, cucumber

(Zucchini / Courgette) – and Zucchini/ courgette yellow mosaic viruses

Sugar beet – Resistance to glyphosate, glufosinate herbicides

Sugarcane – Resistance to certain pesticides, high sucrose content

Sweet peppers – Resistance to cucumber mosaic virus

Tomatoes – Suppression of the enzymes polygalacturonase (PG), retarding fruit softening after harvesting

Wheat – Resistance to glyphosate herbicide

genetically modified crops

Some Examples of – Genetically Modified Crops

Benefits of Genetically Modified Crops(GM Crops)

GM foods are genetically modified such that it will benefit mankind in terms of what we eat. There are two main aspects that can be improved by genetic modification: Alteration of input traits: Resistance to pests and harmful factors, Resistance to pesticide, herbicide, Resistance to disease and virus. Alteration of output traits: Increased output of crops, Increased duration of shelf life, Increased nutritional value, Increased health benefits, Medical benefits – As stated in the characteristics above, these alterations make GM foods a good choice in the market. GM crops can be modified to be resistant to pest as well as pesticides and herbicides. It means that it is healthier than normal foods as they are either pesticides-free or pesticide-resistant, which means that we do not have to eat pesticide. Overall better for our health, just like organic plants. GM crops can also be made to resist disease (fungal, bacterial, viral) and other drastic environmental (drought, salinity, frost, nitrogen starvation) conditions. This means that there is a high probability that these crops can survive widespread diseases as well as droughts or floods. This increase gross output of crops, GM foods can be modified to have a longer shelf life such that it can be stored for longer periods of time without going bad. This is good for the marketability of the crops as they can be kept for a long time before being sold or consumed. GM crops are mostly altered for extra nutritional value for more health benefits. This includes modifying crops so that they produce an extra amount of healthy substances such as vitamins as well as things like Iron and antioxidants. Certain Genetically modified crops (GM crops) such as bananas can be modified such that they serve as vaccines to certain diseases. These vaccines can be ingested along with the banana, making it convenient and less painful than injections. GM crops can also be modified to yield a higher gross output amount than normal crops. This leads to a higher income when selling crops for commercial farmers. Algae, both hybrid, and GM, is under development by several companies for the production of biofuels. Jatropha has also been modified to improve its qualities for fuel product. Swiss-based Syngenta has received USDA approval to market a maize seed trademarked Enogen, which has been genetically modified to convert its own starch to sugar to speed the process of making ethanol for biofuel. The GM oilseed crops on the market today offer improved oil profiles for processing or healthier edible oils. Genetically modified plants have also been used for bioremediation of contaminated soils. Mercury, selenium and organic pollutants such as polychlorinated biphenyls (PCBs), TNT and RDX explosive contaminants have been removed from soils by transgenic plants containing genes for bacterial enzymes.

Safety concerns

Critics have objected to Genetically modified crops (GM crops) grounds, including ecological concerns, and economic concerns raised by the facts these organisms are subject to intellectual property law. GM crops also are involved in controversies over GM food with respect to whether food produced from GM crops is safe and whether GM crops are needed to address the world’s food needs. GM crops might pose health risks to consumers through none of such cases have been documented.

Effect on ecosystems – Reducing the numbers of pest insects in farmland and impacting biodiversity, or by decreasing the use of insecticides. The risk and effects of horizontal gene transfer have also been cited as concerns, with the possibility that genes might spread from modified crops to wild relatives. Reduced effectiveness of pesticides as insects become resistant to engineered toxins. Loss of biodiversity, harm to other organisms, pollen from Bt corn was shown to cause high mortality rates in monarch butterfly larvae. But follow-up studies have shown that the exposure levels in the fields are negligible. Rats fed potatoes genetically modified to contain lectin, a natural insecticide in snowdrop plants, had stunted growth and immune system damage. Rats fed on GM corn showed differences in kidney size and blood composition. However, it was argued that the differences were not biologically significant.

Potential Environmental Hazards – gene may be transferred to non-target species. Herbicide resistant plants and weeds could cross breed and create “superweeds”.

Potential Human Health Risks – genetic engineering could potential introduce or create allergens. For example, inserting genes from a nut into another plant could be dangerous for people who are allergic to nuts. There is always an unknown health risk. Biological processes involve a lot of interactions; it is often difficult to identify every possible interaction. Portions of transgenic DNA had ‘horizontally’ transformed from GM food into the intestinal bacteria of some of the volunteers. Another rat feeding: unexplained changes in testicle cells, an indicator of toxins. Bt toxin is present in all the cells in Bt maize, the main GM maize used in animal feed. The study in toxic reactions in rats showed that rat fed with GM soy showed a five-fold increase in mortality, lower birth weights, and the inability to reproduce.

Economic Hazards – Elimination of competition, GM seeds are patented, Suicide seeds, Plant with sterile seeds that are infertile are created, farmers are forced to buy seeds every year, However, some companies have reduced costs or donated GM seeds.

“Despite dire predictions, no adverse effects of Genetically modified crops(GM crops) on health, biodiversity and the environment have been documented to date.” So are Genetically modified crops/GM foods a good or bad thing, it depends on each individual case. Consumers, the government, and scientists should be responsible for weighing the benefits against the costs.

Since the creation of the first transgenic plants, health issues concerning the safety of GM foods and feeds have been discussed, debated, and evaluated. Through evaluation of scientific data from several disciplines related to genetic engineering and food safety and consultation with experts from around the world, the FDA has established guidelines for the safe commercial introduction of food from GM crops. Any such foods that meet FDA guidelines are deemed to be as safe as other foods on the market.

Genetically-modified foods have the potential to solve many of the world’s hunger and malnutrition problems and to help protect and preserve the environment by increasing yield and reducing reliance upon chemical pesticides and herbicides. Yet there are many challenges ahead for governments, especially in the areas of safety testing, regulation, international policy and food labeling. Many people feel that genetic engineering is the inevitable wave of the future and that we cannot afford to ignore a technology that has such enormous potential benefits. However, we must proceed with caution to avoid causing unintended harm to human and the environment as a result of our enthusiasm for this powerful technology.


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