GMO? Or Non-GMO? That is the question!
Consumers are continuously perplexed by the terminology used within agriculture. Seed selection, plant breeding, and hybridization, for example, are often confused with genetic engineering (often referred to as GMO). Genetic engineering vastly differs from these other practices, as it utilizes a gene splicing technique to insert foreign genetic material into another organism’s DNA. This type of modification cannot occur on its own in nature. In contrast, seed selection, breeding, and hybridization are interrelated practices that can occur naturally and have been used in agriculture for centuries.
Seed selection is a tedious but beneficial process done by farmers throughout all of history. Throughout each season, crops are monitored for productivity, disease and pest resistance, adaptability to surrounding environment, length of maturity, and overall viability of product. At the end of the season, the crops with the best traits are selected and seeds are saved for consecutive growing seasons. This practice has not only improved crop quality and yield over time, but also has adapted seeds to the local microclimates and soil types in which the crops were grown. (Bass et al., 2).
Similarly, plant breeding is the “genetic improvement of crop plants through the study and application of genetics, statistics, agronomy, plant pathology, entomology, and related sciences” (“Plant Breeding,” Department of Agronomy
, 1). This practice can be compared to creating a new dog breed or breed of livestock. The results are not always precise, but genetic changes do happen. These changes can be reasonably controlled through repeated breeding and careful selection, often leading to improved productivity over the parent cross. Selection is simply based off of a desired phenotype
and all the rest of the breeding process is left to nature. Plant breeding utilizes similar selection practices associated with seed selection, but specifically focuses on genetic variation within a species, as natural breeding can only occur within the same species. The genetic variation is created by mutations. Plants with favorable alleles
are selected and allowed to reproduce naturally, thus accumulating “favorable alleles at many loci
affecting the selected trait” (Tracy, 2). These alleles recombine over time, “often resulting in completely novel and unexpected individuals” (Tracy, 2). Hybridization is essentially more specific plant breeding. The object is “to combine desirable genes found in two or more different varieties and to produce pure-breeding progeny superior in many respects to the parental types” (“Plant Breeding,” Encyclopaedia Britannica
, 1). This was first discovered by Edward East and George Shull, who found that two self-pollinating plants could be cross-pollinated to produce hybrid progeny, resulting in improved yields and overall vitality. This is also where the term “hybrid vigor” originated.
While these practices are a form of genetic modification, they utilize natural means to achieve variances in genetic composition within a species. Pluots, for example, are a hybrid cross between a plum and an apricot, both of which are from the same Prunus
species. Genetic engineering is a new type of modification, often referred to as transgenics, that specifically removes sections of DNA from one organism and transfers that section to another organism via gene splicing technique, thus overcoming the natural breeding barrier between species (“Overview of the Process of Plant Genetic Engineering,” 1). This means that DNA from any living organism can be transferred into a plant, thus adding new genetic material that would not otherwise occur in this plant. Traditional plant breeding and hybridization cannot achieve the same results. There are a variety of methods used to successfully transfer the extracted genes into the recipient organism: using viruses or bacteria, which infect the recipient with the new DNA; using biolistic DNA delivery
; and “using electric shocks to create holes in the membrane covering sperm, and then forcing the new DNA into the sperm through these holes” (“The GE Process,” 1). Bt-Corn, for example, contains Bacillus thuringiensis
, a naturally occurring soil bacterium that produces a specific protein that kills larvae like the European corn borer (“Bt-Corn: What It Is and How It Works,” 1). This type of transgenics allows the plant to produce its own pesticide, which would otherwise not occur naturally in this plant. DNA extraction, gene cloning, gene design, and gene transformation are incredibly meticulous steps that can only be done under controlled conditions within a lab. The final step is backcross breeding, which “combines the desired traits of elite parents and the transgene into a single line,” ultimately following traditional plant breeding methods to enforce the genetic change (“Overview of the Process of Plant Genetic Engineering,” 1).
Modern transgenics, commonly termed GMO, is a relatively recent scientific discovery. In 1973, Herbert Boyer and Stanley Cohen produced the first successful GMO via gene splicing technique (Rangel, 1). The first genetically engineered (GE) seed patents were approved in 1980 by the U.S. Supreme Court and experimentation with food crops began seven years later (Rangel, 1). The first GE crop was not released to the public until 1992, with the first insecticide-producing potato following three years later (Rangel, 1). The World Health Organization defines the term GMO as “organisms (i.e. plants, animals, or microorganisms) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination. The technology is often called ‘modern biotechnology’ or ‘gene technology,’ sometimes also ‘recombinant DNA technology’ or ‘genetic engineering.’ It allows selected individual genes to be transferred from one organism into another, also between nonrelated species” (“Q&A: genetically modified food,” 1).
In conclusion, seed selection, plant breeding, and hybridization are practices that have occurred for centuries. These practices can theoretically be referred to as genetic modification within a species, as the end result does alter the genetic composition of that species. However, the term GMO and genetic engineering is generally applied to biotechnology practices done today via gene splicing technique, which allows foreign genetic material to be inserted into an organism. The main difference between GMO and Non-GMO products is whether or not the result was achieved through natural or artificial means. The National Organic Program does not allow the use of GMOs and is constantly seeking to improve protocols to eliminate cross-contamination from pollination and wind drift.
Phenotype: the physical and biochemical characteristics of an organism as determined by the interaction of its genetic constitution and the environment. Source: http://www.dictionary.com/browse/phenotype?s=t
Allele: any of the possible forms in which a gene for a specific trait can occur. In almost all animal cells, two alleles for each gene are inherited, one from each parent. Source: http://www.dictionary.com/browse/allele
Loci: the position of a particular gene on a chromosome. Source: http://www.dictionary.com/browse/loci?s=t
Biolistic DNA delivery: literally shooting DNA into cells. The DNA is coated onto microprojectiles, which are accelerated by the macroprojectile on firing the gun. Other methods are driven by compressed gas instead of a gunpowder charge. Source: An Introduction to Genetic Engineering
, by Desmond S. T. Nicholl.
“Overview of the Process of Plant Genetic Engineering.” AgBiosafety Crop Technology.
University of Nebraska-Lincoln, n.d. Web. 7 Apr. 2017. http://agbiosafety.unl.edu/education/summary.htm
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, n.d. Iowa State University.
Web. 6 Apr. 2017. http://www.agron.iastate.edu/academic/graduate/plantbreeding.aspx
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Bass, Jared C., Jillian M. Lowery, Chlutch Luabun, Ghazal Rashidi, and Lauren M. White. "Re-establishing the practice of farmer's selecting and saving their own seeds to promote adaptation to local micro-climates as well as disease and pest resistance." Governor’s School for Agriculture,
2011. Virginia Polytechnic Institute and State University
. Web. 6 Apr. 2017. <https://www.researchgate.net/publication/265067182_Re-establishing_the_practice_of_farmer%27s_selecting_and_saving_th eir_own_seeds_to_promote_adaptation_to_local_micro- climates_as_well_as_disease_and_pest_resistance>
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Rangel, Gabriel. “From Corgis to Corn: A Brief Look at the Long History of GMO Technology.” Science in the News
. Harvard University, 23 Oct. 2016. Web. 7 Apr. 2017. http://sitn.hms.harvard.edu/flash/2015/from-corgis-to-corn-a-brief-look-at-the-long-history-of-gmo-technology/
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, n.d. University of Wisconsin-Madison.
Web. 6 Apr. 2017. http://croptechnology.unl.edu/Image/LeingangDeanna1129928877/Tracy.WhatIsPlantBreeding.pdf
*Photo credit: http://beyond-gm.org/gmo-or-gm-no-how-will-the-eu-regulate-new-plant-breeding-technologies/