GM Foods
Feeding the World
What's a GMO?
Genetically Modified Organisms (GMOs) are organisms whose genetic material (DNA) has been altered in a way that does not occur by mating and/or natural recombination. Genetically modified foods allow for select individual genes to be transferred from one organism into another, also between non related species.
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How to make a GMO:
Step 1: Identifying a trait of interest
The first step of making a GMO is deciding which trait you want the crop to express. Resistance to herbicide, resistance to extreme environmental factors, resistance to viruses/diseases, and a more nutritional composition are examples of some of these beneficial genetic modifications.
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Step 2: Isolating the Gene that codes for the trait of interest
In order to isolate the Gene of interest from the genome of an organism which expresses the desired trait, comparative analysis is utilized. The genomes of organisms with the trait are compared to the genomes of the organisms of the same species without the trait. Genes present in only the former must code for the trait that the second lacks.
Step 3: Inserting the gene of interest into the genome of the crop
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There are multiple ways to do this. One way is with a gene gun which shoots metal particles coated with DNA into plant cells with a .22-caliber charge. Another way to do this is to utilize bacteria which are known to invade cells and plant their DNA into a plant’s genome. An enzyme is used to cut and paste a DNA strand of interest into a plasmid, a small circular molecule of DNA. The bacteria are then shocked so that they accept the engineered plasmid and begin to produce the gene of interest in their own DNA. The bacteria with the new genetic information is then used to invade the plant cell so that the gene of interest enters into the plant cells’ DNA and becomes a part of its genome.
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Step 4: Grow the GMO
When the gene is successfully inserted into an organism's DNA the organism must be able to be grown and replicated while expressing the desired trait. Once the crop has been successfully reproduced and expresses the desired trait, Biotechnology companies invest in them to ensure they continue being produced by using special climate-controlled growth chambers.
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The development of GMOs
Genetically modified organisms have manifested themselves in agriculture before recorded history. To maximize profit, prehistoric farmers have always selected their most productive seeds to re plant and their best livestock to breed. Since the last quarter of the 20th century, traditional methods of selectively breeding organisms with desired traits have changed drastically. Using modern day technology, scientists are able to select productive traits at the individual gene level and implement them into the genome of new organisms. These methods that are utilized today are far more precise in producing organisms with desirable traits and also allow for the transfer of genes from two completely different organisms. An example of this would be how in 2000, the concentration of vitamin A in tomatoes was increased by adding a bacterial gene which encodes phytoene desaturase.
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Various Applications of GM Crops
Biofortification
Deficiencies in micronutrients such as zinc, iron and vitamin A (VA) can cause profound and irreparable damage to the body. Blindness, growth stunting, mental retardation, learning disabilities, low work capacity, and even premature death are other effects of VA defficency! Deficiency in micronutrients is commonly called “hidden hunger”. People in impoverished countries typically suffer from micronutrient deficiencies not because they don’t have enough food to eat, but because their food is not as nutritious as it needs to be. The genetic modification of staple food crops such as rice, corn, beans, etc. can increase the amount of micronutrients contained in the crop and subsequently make the crop more nutritious. This process is known as biofortification and has the potential to improve the diets of millions of people.
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GM foods such as the Orange fleshed sweetpotato (OFSP) have shows promise as they are engineered to be more micronutrient rich. OFSP, when coupled with community nutritional education, provides high levels of vitamin A to vulnerable populations, especially women and young children. One small boiled root of most OFSP varieties provides 100% of the recommended daily intake of vitamin A for children and one medium root provides all of the needs for most women of reproductive age. The International Potato Center (CIP) is working to bring the nutritional benefits of OFSP to nearly 2 million households in countries across sub-Saharan Africa affected by vitamin A deficiency.
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Potential to Lessen Pesticide Use
The main reason farmers use pesticides is to protect their crops and yields from insects. The World Health Organization reports 220,000 people die every year worldwide because of pesticide poisoning. Although most pesticides (80%) are used in the rich countries, most of the poisonings are in poor countries. This is because safety standards are poor. There may be no protective clothing or washing facilities, while there is insufficient enforcement, and poor labeling of pesticides.
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Timeline of the introduction of Bt corn into cornfields and the concurrent reduction of insecticide usage in these fields. The two quantities are strongly anti-correlated, suggesting that this Bt crop has made synthetic insecticides unnecessary
Luckily, crops can be genetically modified so that they themselves can be resistant to some forms of insects. For example, some crops such as corn, cotton, and soybeans have been genetically engineered to express the Bacillus thuringiensis (Bt) gene which is naturally occurring in bacteria in the soil. Bt produces proteins specifically active against certain insects. As shown in the figure below, the two quantities of percent hectare Bt corn and Insecticide use are strongly anti-correlated, suggesting that this Bt crop has made synthetic insecticides unnecessary. GM crops have the potential to eliminate the need for pesticides all together which could prevent hundreds of thousands of deaths globally.
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Giving Crops Resistance to Viruses
The lush Tropical Islands of the Hawaiian chain are an ideal place to grow fruit. Papaya is the second most important Hawaiian fruit crop (pineapples are the first). In spite of ideal growing conditions, plant diseases are also present. Papaya ringspot virus was first detected in the 1940s and began affecting crop yields by the 1950s. By the late 1990s, papaya ringspot virus had affected every papaya producing region, resulting in production dropping by over 50% between 1993 and 2006.
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The Hawaii Department of Agriculture began funding research into a genetically modified variety of papaya that would be resistant to the ringspot virus in 1985. By 1992, field trials had began to gather data about how successful the GM papaya would be in resisting the ringspot virus. The success of field trials led to the 1995 submission for regulatory approval to commercially produce GM papaya. Within two years of production approval, GM papaya accounted for over half of all the papaya production. Ten years later, GM papaya accounted for over 90% of papaya production.
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