Transgenic foods are those living organisms to which their DNA is modified so that they have a piece of DNA from another organism and that they can be consumed . This is achieved through genetic engineering techniques or molecular biology.
Genetic modification is thanks to the fact that all living organisms have DNA as a genetic information molecule. These can be done in bacteria, fungi, plants and animals. Although transgenic foods are genetically modified organisms (GMOs), not all GMOs are transgenic.
Animals or plants that are not modified are known as wild species . Transgenic animals are widely used in scientific research or in the production of medicines. Its use for purposes of mass consumption, agriculture or commerce is reduced. In 2016, commercialization of genetically modified salmon began.
Plants such as corn, potatoes and tomatoes were the first to be genetically modified.
Steps to develop genetically modified foods
The production of transgenic foods follows several stages, which we describe below.
First step: selection of special feature
The special characteristic with which you want to modify must be studied. For example, Bacillus thuringiensis (Bt) is a bacterium that produces crystals that are toxic to many insects that damage plants. These crystals are produced by a protein that is encoded by a gene in the bacteria. By molecular biology techniques, the gene for this protein can be obtained.
Second step: transformation of plants or animals
Once the gene is selected, there are several methods to introduce the gene into the genome of the plant or animal of interest.
For plants, one of the most used methods is the bacterium Agrobacterium tumefaciens. This bacterium is capable of transferring pieces of DNA called plasmids. These plasmids can insert the gene into the genome of the plant to produce the protein that is encoded.
There are also plasmids that can be used for the transformation of animal cells.
Other techniques for introducing genes into plants are by bombardment of genes and by microinjection within the nucleus of the plant.
Third step: production of the special feature in the plant or animal
Corn with the Bt gene of Bacillus thuringiensis bacteria can be protected against insect attack.
Once the foreign gene is incorporated into the genome, plants or animals can begin to synthesize the special protein. For example, some plants produce their own Bt toxin and thus protect themselves against the damage that some insects cause. A cotton plant with the Bt gene is known as Bt cotton.
An animal that was genetically modified to express the growth hormone of another animal will begin to produce that hormone.
Advantages of genetically modified foods
Thanks to scientific advances and the knowledge acquired in genetic manipulation, the production of transgenic foods represents a substantial evolutionary step.
Knowing the processes of degradation and decomposition of food, strategies have been created to increase the useful time of a vegetable, in order to facilitate transportation and the time of use of such food.
Ensure the obtaining of nutrients
With genetic modification, foods that contain nutrients necessary for human consumption can be produced, such as vitamins, antioxidants, which in certain populations is difficult to achieve with natural sources. This is the case of golden rice.
With the use of Bt plants, the use of pesticides is reduced
By producing plants that directly express their weapon against the insects that attack them, the amount of pesticides and insecticides that could simultaneously be consumed by animals and humans, with potentially harmful effects, is reduced.
Resistance against drought, insects, fungi and other harmful agents
The most important intention of the creation of genetically modified organisms is to protect them from the damage they can suffer from other natural agents. This protection will also benefit human beings, since it will increase the production of food that can not otherwise be consumed.
Anticipating the possible consequences of climate change, there is also the possibility of protecting plants that can withstand droughts and high temperatures.
Disadvantages of transgenic foods
As in all technological advances, its application can be distorted for detrimental purposes. For this there are a series of controls and regulatory bodies responsible for approving or not the use of such foods.
Potential environmental consequences
Organizations that oppose the spread of GM foods express that genetically modified plants and animals can lead to environmental damage.
Impact on biodiversity
Many detractors of genetically modified organisms maintain that these will have the advantage of growth and development, causing the loss of wild species. The use of Bt protein may cause the disappearance of insect species.
Impacts on health
One of the major concerns of the consumption of transgenic foods is their potential allergenic effect. However, the possibility of a transgenic food producing allergy is the same as any other food. Therefore, a person allergic to strawberries or peanuts should be careful to consume a transgenic food that has some compound from these foods.
Another criticism of GM foods about health is that mutations are created in those who consume the product. This has also been shown that it is not possible.
The production of genetically modified plants and animals is mostly carried out by large companies. These seek their economic benefit and have strategies so that farmers can only depend on them.
Examples of transgenic foods
There are currently some transgenic foods available to the public, most of them for the feeding of farm animals. Let’s see some examples.
The Flavr Savr tomato stopped being commercialized in 1999 due to lack of profitability.
The first transgenic food that was commercialized was the Flavr Savr tomato, in 1994. The process of maturation and decomposition of this tomato was reduced. In this case, an antisense gene was used that prevented the production of polygalacturonase, an enzyme that breaks the cell wall of the fruit.
The red color of tomato ( Solanum lycopersicum ) is due to the accumulation of carotenoid pigments, called lycopene and phytoene. Anthocyanins are purple pigments that have anti-inflammatory and antioxidant properties. In 2008, a tomato was produced with two genes from the mouth of the dragon Antirrhinum majus , which increased the content of anthocyanins, and with it the color purple.
Rice ( Oryza sativa) is one of the most consumed foods worldwide. In many regions where rice is the main source of food there is a deficiency of vitamin A, which is associated with vision problems. Golden rice is a variety of rice genetically engineered to produce beta-carotenes, which is the precursor of vitamin A.
Fast-growing transgenic salmon
The transgenic Salmon AquAdvantage is ready for sale in half the time of the wild salmon.
In Canada and Panama, genetically modified AquAdvantage salmon is being produced from Atlantic salmon ( Salmo salar ). This has a recombinant DNA with the Chinook salmon growth hormone gene ( Oncorhynchus tshawytscha ), which makes it grow faster.
Papaya Rainbow Hawaiian
Papaya ( Carica papaya ) is a tropical fruit widely grown in the Hawaiian Islands. The plant suffers from a disease caused by a PRSV virus that practically decimated papaya production in the nineties of the 20th century. Thanks to biotechnology, a papaya could be produced that contained part of the virus in its genome, making it resistant to the attack of foreign viruses.
Soybean resistant to glyphosate from Monsanto
Glyphosate is a chemical compound with a herbicidal effect. In agriculture it began to be used to reduce the competition of herbs in the main crops; however, glyphosate also affects cultivated plants. It was possible to produce plants with a gene that inhibits the effect of glyphosate, making these plants resistant to glyphosate. In this way, farmers could planted their seeds glyphosate resistant, and at the same time fumigate with the product to eliminate the herbs.
The most widely used glyphosate-resistant plants are soybean, corn and canola.
All the legal aspects concerning GMOs in Mexico are regulated by the Biosafety Law of genetically modified organisms of 2005. For 2013, Mexico cultivated transgenic cotton and soybeans. However, the permit for commercial soybean cultivation was revoked in 2017.
On the other hand, the cultivation of transgenic corn has a cultural aspect that is more difficult to surpass. Native Mexican corn was declared a cultural and agricultural heritage of Mexico, which is why the cultivation of genetically modified corn species is restricted. In 2017, Mexico imported a third of corn for consumption, probably transgenic corn from the United States.
Mexican researchers developed a corn that needs only two thirds of the water from a normal plant in what is known as the Xoconostle project. The cultivation of transgenic corn could increase production and benefit both farmers and consumers.
From hybridization to transgenic foods
For more than 3000 years, farmers have developed different techniques to select varieties of plants and animals with the best properties.
The evolution of agriculture can be classified in three stages:
- the farmers searched and selected the most efficient plants and animals and used them.
- The farmers recognized that natural crops could be improved by cross-linking or hybridization.
- Genetic engineering techniques appear.
The crossing of different animal or plant species to give rise to a new species is known as hybridization . This was the first effort of human beings to create new species that were not found in nature. The classic example is the crossing of a donkey with a mare, which produces a mule.
The objectives of the genetic manipulation of animals and plants for human consumption are the following:
- improve crop production by accelerating growth;
- make crops resistant to insects, pathogens and other pests;
- improve the nutritional quality.