Wednesday, June 5, 2013

The [Real] Facts About Genetically Modified Organisms

    The European Food Safety Authority (EFSA) defines a "Genetically Modified Organism", or GMO, as "an organism in which the genetic material has been altered in a way that does not occur naturally through fertilisation and/or natural recombination. GMOs may be plants, animals or micro-organisms, such as bacteria, parasites and fungi." 'Genetically engineered' (GE) is an alternative term used to refer to the manipulation of these species to produce or promote particular traits.  It is difficult to determine the origin of the term "Genetically Modified Organism", or GMO, but it is known that people have been attempting to exploit and select for desirable traits in agriculture for hundreds and perhaps thousands of years.

History of GMOs
While the ability to manipulate DNA is a relatively recent technology, farmers since prehistoric times have used selective breeding and hybridization to increase the frequency of desirable traits within the crop population.  The study of genetic inheritance by Mendel further increased recognition of the benefits of selective breeding around the onset of the 20th century.  Many of the "normal" crops which exist today are a result of extreme selective breeding and would never have existed on their own; early farmers isolated the genetic outliers of a crop population that exhibited the most advantageous traits in order to improve future yields, selecting on the basis of size, fruit production and other desirable characteristics.  

     The first published reports of genetic engineering date back to 1972 when Paul Berg successfully spliced foreign genes into a circular viral DNA molecule, followed by the first bacterial transformation utilizing genetically engineered DNA in 1973.  This 1980s saw the first industrial and medical applications of this technology, with the creation of oil-eating bacteria by Exxon and the production of human insulin in bacteria by Genentech. Genetic engineering is now an integral tool for laboratory research, industrial technologies and many medical applications.  While little controversy exists concerning most applications of genetic engineering, the use of genetically modified crops in the agricultural industry has received much public backlash over the past few years.

     Agricultural biotechnology has been experimenting with genetic manipulation of plant varieties since the late 1920s, originally through the use of ionizing radiation, which induces mutations randomly within the genome.  Today’s practice of selectively genetically engineering plants is much more precise and efficient than randomly mutated plants, because scientists are able to select the specific traits they wish to be included in the target organism. The first GMO tested in the environment was the "ice-minus" P. syringae bacterium in 1987, which prevented frost formation when sprayed on the surface of plants.  The first commercially available GM crop was the FlavrSavr tomato, released in 1994, which exhibited an extended shelf life.  Other common agricultural GMOs that followed include insect-resistant Bt (B. thuringiensis) plants and the commonly used glycophosphate herbicide-resistant (Roundup Ready) crops.

Agricultural Benefits
     The advent of GM crops has had significant economic benefits on the agricultural industry worldwide, especially in developing nations, although accounting for all variables when determining the true economic effects of GMOs is difficult.  The increased abundance of insect and herbicide-resistant GM crops has also been shown to reduce pesticide use and associated greenhouse gas emissions, although recent outbreaks of herbicide-resistant weeds may have counteracted this effect and the true environmental impact of GMOs is yet to be fully determined. By eliminating crop loss and allowing more efficient cultivation, a major outcome of increased GMO use has significantly improved crop yield compared with non-engineered crop fields.  In addition to increasing yield, GM crops can greatly benefit developing nations through enrichment of nutrients typically lacking within the regional population.  

Reasons for GMO Mistrust
     There seem to be many complex reasons why a multitude of nations, organizations and individual citizens have recently made public stands against GMOs. Overall, the aversion of GMOs appears to derive from (i) the lay public's 
unfamiliarity with and often bias against science, (ii) legitimate concerns about potential long-term environmental effects, (iii) a preponderance of bad pseudoscientific anti-GMO studies, and (iv) general distrust against the economic motivations of Monsanto and other corporations involved with GMO production.  Together, all of these factors build on each other, feeding on fear-mongering in the media and creating a mob mentality of revulsion towards GMOs.

Health and Safety Studies
     A few studies have been published claiming to show toxicity in animals resulting from exposure to GM crops. One of the most famous early studies was published in 1999 by Arbad Pusztai, measuring the effect of potatoes engineered to produce GNA lectin on intestinal thickness in rats .  Pusztai reported that the presence of the transgene had a significant effect on intestinal thickness and proliferation, while also claiming separately in an interview that negative impacts on growth and immunity were also observed.  In addition to receiving criticism on both his controls and conclusions, there were also major issues with the peer review process. Unfortunately it is difficult to assess the validity of both the study and its criticisms because upon presenting his findings, Pusztai was suspended by the Institute that originally commissioned and later disparaged the study.
     Another popular report published in 1999 determined that ingestion of pollen from Bt maize in a laboratory setting was detrimental to the growth and viability of monarch butterflies, however a series of subsequent studies determined that when accounting for real-world dosage and exposure Bt plants do not pose any legitimate risk to non-target species.  More recently, Gilles-Eric Séralini published a series of anti-GMO papers from 2007-2011 that reanalyzed previous published data and concluded that various strains of GM maize caused organ damage in rats.  The EFSA and other organizations concluded that any measured differences among the various parameters studied remained within the limits of natural variation and therefore did not suggest any harm from GMO food.  In 2012 Séralini then published one of the most cited and controversial papers in the GMO debate, where he claimed that rats ingesting Roundup-resistant maize or Roundup itself were highly prone to cancer and organ damage.  While this study is praised by GMO opponents, it also produced widespread criticism and even condemnation by the scientific community.  Detractors of the study commented on poor statistical power, use of tumor-prone rat models, length of the study relative to average lifespan and other issues.  It also appears that Séralini may have wished to utilize the publication for self-promotion, as the paper was uncharacteristically advertised with a press conference that he also used to market a book and film about the research. Fears about potential effects of GM crops on human health are unfounded, and the safety of ingesting genetically engineered food has been confirmed multiple times by various organizations including AAAS, the American Medical Association and the European Commission.  These organizations also argue against mandating labeling of GM food, stating that requiring the labeling of foods that pose no known health risk could mislead and falsely alarm consumers (from the AMA).
Environmental Issues
     While fears about health risks from ingesting GM food are mostly exaggerated or unfounded, there are some legitimate environmental concerns about the presence of GM crops in a mixed ecosystem with other non-GM plants and animals.  Gene flow from GMOs into other organisms, especially of resistance genes, is a potential problem that could lead to "superweeds" or substantial changes in the balance of the surrounding ecosystem (although it is possible that weed species may naturally evolve resistance over time).  Resistant weeds may lead to overspraying of herbicides, which has been shown to reduce biological diversity. While government regulation and "Terminator" technology aim to restrict unintentional gene transfer (likely by crossbreeding), researchers have found some instances of engineered genes appearing in non-GM plants.  Ironically, protests against Terminator technology have forced Monsanto to pledge not to commercialize it, therefore further promoting the gene flow for which their GMOs are criticized.  A related issue is the escape of GM plants into distant fields or crop shipments, increasing the risk of gene flow and potentially causing economic issues if contaminating crops that are exported to nations with a ban on GMOs.  The recent discovery of a discontinued non-approved GM wheat strain in Oregon highlights this problem and was even parodied on the Colbert Report.  

Monsanto Corporation
   Independent of any real or perceived dangers of GMOs, a large reason for the anti-GMO sentiments is a general distrust for Monsanto and other large agricultural corporations that create and distribute GM crops.  Many consumers believe that Monsanto exhibits unfair business practices and are upset about its history of toxic chemical production.  While the toxic side effects of Agent Orange and other former Monsanto products are certainly regrettable, one cannot simply discount the safety of GMOs because of past mistakes.  Many protestors criticize that Monsanto's strict patent enforcement has resulted in lawsuits against innocent farmers due to accidental contamination of their fields from gene flow of nearby GMO crops.  Monsanto has brought only 11 cases to trial for patent infringement, and among the most well-known is Monsanto Canada Inc. v. Schmeiser, involving the illegal cultivation of Roundup-resistant canola originated from a nearby source.  While the myth exists that Monsanto sued Mr Schmeiser upon finding any presence of patented GMOs on his farm, in reality he purposely saved the GM seed and planted it in his field the following season despite a warning from Monsanto.  Tests confirmed that his field the following season was "95 to 98 percent Roundup resistant", and 3 independent courts confirmed that Mr Schmeiser willingly isolated and replanted GM seed without a license.

     The GMO literature is littered with pseudoscience, biased reports and fearmongering.  Just like any other new technology, genetic engineering does involve some potential risk, both predicted and unforeseen.  People tend to be afraid of what is new or unknown, preferring "natural" foods and methodologies.  As others have articulated, "natural" is a subjective term.  Arsenic is natural, many antibiotics and anti-cancer drugs are not.  GMOs utilize the "natural" processes of gene splicing and recombination, except controlled by humans to ensure that only beneficial traits are selected.  The economic motives and environmental effects of GMO-dominated agriculture are complex issues that should be discussed, but only in the context of peer-reviewed unbiased studies, and with the knowledge that human health is not significantly affected.  

Always check the origin of your sources, and evaluate with an open mind.

For a quality paper on anti-GMO biases (albeit full of some opinion itself) here.

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