Biosafety And Detection Of Genetically Modified Organisms
21Biosafety and Detection ofGenetically Modified OrganismsJuliano Lino Ferreira1, Geraldo Magela de Almeida Cançado1,Aluízio Borém2, Wellington Silva Gomes2 and Tesfahun Alemu Setotaw11PlantBiotechnology Laboratory, Agricultural Research Agency ofMinas Gerais - EPAMIG, Caldas – MG,2Department of Crop Science, Universidade Federal de Viçosa, Viçosa-MG,Brazil1. IntroductionBiosafety is a set of actions focused on preventing, minimizing and eliminating risksassociated with research, production, teaching, use, technology development and servicesrelated to genetically modified organisms (GMOs) with the aims of protecting human andanimal health and environmental preservation.Transgenic organisms, or GMOs, are organisms in which genetic material has been alteredby recombinant DNA technology. Biotechnology allows the insertion of one or more genesinto the genome of an organism from a different organism or species (e.g., animals, plants,viruses, bacteria); the expression of the introduced gene results in a new feature in thephenotype of the modified organism. A shortened definition of genes is that they are DNAsequences that contain the necessary information to affect phenotypic expression in anorganism, such as the shape of a seed or resistance to a specific pest. The informationencoded by the gene is expressed through two principal steps: transcription, in which thecoding region of the DNA is copied into single-stranded RNA; and translation, in which theamino acid sequence encoded by mRNA is assembled and translated into protein. Thus, forthe creation of a GMO, it is necessary to introduce the gene responsible for a particular traitinto the genome of the target organism through recombinant DNA techniques.Several products derived from recombinant DNA technology are commercially availableworldwide. GMO products already on the market include human insulin, somatropin andtransgenic varieties of crops, such as maize, soybeans, cotton and common beans. TheUnited States, Brazil and Argentina are among the principal countries engaged in thecommercial production and marketing of GMOs (James, 2010).The emergence of genetic engineering in the early 1970s in California, USA, with theisolation, introduction, and expression of the insulin gene in Escherichia coli provoked astrong reaction from the scientific community all over the world, which led to the AsilomarConference in 1974. At that time, the scientific community proposed a moratorium ongenetic engineering. They argued that rules and safeguards should be established to ensurewww.intechopen.com
428Transgenic Plants – Advances and Limitationsthe use of genetic engineering techniques without risking human life and the environment.In a relatively short period of time, biosafety regulations were developed for the appropriateuse of these technologies in the laboratory. After over 35 years of research on andcommercial use of biotechnology, there have yet to be any reports about the adverse effectsof the use of genetic engineering on human and animal health or the environment.Therefore, to ensure the appropriate generation and utilization of this technology, biosafetyregulations and monitoring mechanisms have been developed in different countries aroundthe world. Several field tests with transgenic varieties have been performed in the USA,Argentina, Bolivia and Chile since 1991. However, in Brazil, these tests only began in 1997.2. Transgenic plants and their advantagesIn the future, there will be difficulties in meeting the food demand in developing countriesdue the increasing trends of food prices and population growth. Therefore, it is necessary toemploy new technologies, such as the use of transgenic varieties, to increase theproductivity per unit area, especially in the developing nations. Qaim and Zilberman (2003)reported that in developing nations (i.e., China, India and Sub-Saharan Africa) farmers canachieve a greater than 60% grain yield advantage by using transgenic plants modified withthe Bt gene instead of conventional varieties. In their work, these authors showed that theyield advantage comes solely from the impact of the Bt gene on the control of insect pests.Biotechnology research currently plays a key role in food production because it helps toincrease productivity, improve the nutritional quality of agricultural products and reduceproduction costs. Qaim and Zilberman (2003) reported that using the Bt gene for the controlof insect pests gave a US 30 per ha advantage over conventional cotton. It is alsoadvantageous because it allows reduction of the use of highly hazardous chemicals, such asorganophosphates, carbamates, and synthetic pyrethroids, which belong to internationaltoxicity classes I and II.The commercialization of transgenic plants in Brazil has also strongly affected theagrochemical sector, which has annual profits of approximately 20 billion US dollars. Ofthis, approximately 8 billion US dollars per year corresponds to pesticides used for thecontrol of diseases, insects and weeds. In some cases, the cost of pesticides in relation to thetotal cost of production reaches approximately 40%, as in cotton. However, varietiesdeveloped by genetic engineering that are tolerant to herbicides and resistant to insects,fungi, bacteria and viruses have led to reductions in the cost of agricultural production and,consequently, reduction of the impact of agrochemical wastes that have an adverse effect onthe environment and human health.The findings described above, obtained in developed and developing nations, demonstratethe contribution of transgenic plants to increasing the productivity per unit area to fulfill theincreasing demand for agricultural products to feed the growing population of the world.GMO technology is currently widely employed throughout the world. The global area ofbiotechnology crop coverage in 2010 reached approximately 148 million ha in 29 countrieson five continents. The major biotechnology crops cultivated worldwide are maize, soybean,canola, cotton, sugar beet, alfalfa and papaya (James, 2010). The geographic distribution ofbiotech crops throughout the world is presented in Table 1.www.intechopen.com
429Biosafety and Detection of Genetically Modified Organisms3. Food biosafetyThe food safety of transgenic plants is assessed in accordance with risk analysis. Thismethodology was initially developed with the aim of assessing deleterious effects on humanhealth arising from potentially toxic chemicals present in food, pesticide residues,contaminants and food additives and was subsequently applied in assessing the food safetyof GM plants.One of the main foundations of risk analysis methodology is that transgenic plants are notinherently more dangerous than conventional crops; i.e., the potential health risks that maybe associated with a transgenic variety are not because it is GM but rather are related to thepossible chemical changes that may result from genetic modification (Konig et al., 2004). Forexample, a genetically modified common bean expressing an allergenic protein from theallergen Brazil Nut (Bertholletia excelsa) was not prohibited from being produced because itwas obtained by genetic engineering, but because the genetic modification was incorporatedin a gene that promotes the synthesis of an allergenic protein in this nSouth AfricaUruguayArea (millions of hectares)66.825.422.99.48.83.52.62.42.21.1Table 1. The ten major producers of transgenic crops in the world (adopted from James,2010)In general, most transgenic plants are modified to synthesize proteins that are absent inconventional varieties. These proteins are encoded by a transgene and introduced preciselyfor the purpose of conferring the desired trait. However, beyond this difference, otherbiochemical changes may result from the introduction of a transgene, and all of this isinvestigated during risk analysis.In the case of transgenic plants, risk analysis is performed by comparing them with theirnon-GM counterparts, which are considered to be safe on the basis of their usage records.In risk analysis, instead of attempting to identify every hazard associated with the GMvariety, one can seek to identify only new hazards that are not present in the traditionalvariety.This type of comparative study is referred to as substantial equivalence analysis and isbased on comparison of the biochemical profile of the transgenic variety with theconventional variety. The GM variety can be classified as substantially equivalent orsubstantially non-equivalent.www.intechopen.com
430Transgenic Plants – Advances and LimitationsAt this point, it should be noted that food security assessment of a GM plant is not restrictedto applying the concept of substantial equivalence. This constitutes only the starting pointfor this assessment, and it aims to identify differences that will be analyzed later. Furtheranalyses include allergenicity and toxicity tests performed in silico, in vitro and in vivo inanimal models (i.e., rodents, birds, fish, and other species) to assess toxicity levels. In thesetests, the LD50 (lethal dose in 50% of cases) is generally determined as an indicator of acute(i.e., short-term) toxicity.The risk assessments are performed in three steps (Borém and Gomes, 2009):Step 1. Risk assessment: This step can be defined as the evaluation of the probability ofadverse health effects arising from human or animal exposure to a hazard. Riskassessment consists of four segments:i. Hazard identification, which entails the identification of biological, chemical andphysical hazards found in food that may cause adverse health effects;ii. Hazard characterization, which entails an evaluation of an identified hazard inqualitative and quantitative terms and often involves the establishment of a doseresponse relationship due to the magnitude of exposure (dose) to a physical, chemical,or biological hazard and the severity of adverse health effects;iii. Exposure assessment, which entails a quantitative and qualitative assessment of thelikelihood of ingestion of physical, chemical and biological agents through food;iv. Risk characterization, which entails a qualitative and quantitative estimation of thelikelihood and severity of an adverse effect on health based on identification andhazard characterization and on exposure assessment.Step 2. Risk management: Risk management is measured from the results of riskassessment and other legitimate factors to reduce risks to the health of consumers.Measure of risk management may include labeling, imposition of conditions formarketing approval and post-trade monitoring.Step 3. Risk communication: Risk communication includes the information exchange thatmust occur between all stakeholders, including the government, industry, thescientific community, media and consumers. It should occur throughout theassessment and risk management processes and should include an explanation tothe public of the decisions made, ensuring access to documents obtained from therisk assessment and, at the same time, respecting the right to safeguard theconfidentiality of industrial information.Food biosafety analyses performed by different national and international organizations,such as the World Health Organization, the International Council for Science, the UnitedNations Food and Agriculture Organization, the Royal Society of London and theNational Academies of Sciences from Brazil, Mexico, India, the United States, Australia,and Italy have demonstrated that transgenic varieties can be considered safe for humanconsumption.4. Environmental biosafetySimilar to food risk assessment, environmental risk assessment considers three importantpoints: the possibility, probability and consequences of a hazard, which should always beassessed on a case-by-case basis. This means that, following the identification of a possiblewww.intechopen.com
Biosafety and Detection of Genetically Modified Organisms431danger, you should consider whether that danger is possible, if it is likely and, if it were tooccur, what the result would be (Conner et al., 2003).In the specific case of risk assessment for GM plants, a fourth point should also beconsidered: the risks of non-adoption of this technology.An essential element in any risk assessment is the establishment of correct benchmarks. Asdescribed for the assessment of food security, a GM crop plant is compared with its non-GMcounterpart. Similarly, the environmental impact of transgenic plants should be evaluated inrelation to the impact caused by conventional varieties.These principles are essential for providing guidance regarding which tests should beconducted and what questions should be answered to generate information that will assistin making the decision to use or not use a specific transgenic variety. Failure to follow theseprinciples can result in unnecessary and unhelpful evaluations in risk assessments.For example, the cultivation of insect-resistant transgenic cotton in Brazil has raisedconcerns about gene escape, i.e., the possibility of the transgenic variety crossing with wildspecies of the genus Gossypium that are native in Brazil and thus sexually compatible withcultivated cotton (Freire and Brandão, 2006). The main issue is the possibility of the pollen oftransgenic cotton plants fertilizing wild cotton. The offspring of such crosses could haveconsequences for the maintenance of genetic diversity, although this point remains verycontroversial, as several research groups do not believe that the introduced gene wouldproduce any adaptive advantage when exposed to the natural environment.Gene escape from transgenic plants can occur in three main ways:i.When the transgenic plant becomes a weed or an invasive species (e.g., for crops withweed-like characteristics, such as sunflower, canola, and rice), the transgenic genefound in the transgenic plant may allow the crop to become weedier and more invasive;ii. Intraspecific and interspecific hybridization, such as when transgenic DNA istransferred by crossing to other varieties of cultivated species and wild species,respectively;iii. When transgenic DNA is asexually transmitted to other species and organisms.For a gene to escape and be transferred to different species, certain conditions are necessary:i.ii.The two parental individuals must be sexually compatible;They must be located in neighboring areas and with flowering overlap between the twoparental types;iii. A sufficient amount of viable pollen must be present and transferred betweenindividuals;iv. The resulting progeny should be fertile and ecologically adapted to environmentalconditions where the parents are located.To avert gene escape from transgenic varieties to conventional varieties, isolation distanceshould be maintained. For example, maize is a wind-pollinated species, and the distancesthat pollen can travel depend on the wind pattern, humidity and temperature. In general,fields with transgenic varieties should be isolated from other conventional varieties with adistance of at least 200 m (Weeks et al., 2007). The risk of gene escape from soybeans andmaize to wild relatives in Brazil is considered by most scientists to be small or nonexistent.www.intechopen.com
432Transgenic Plants – Advances and LimitationsThe risk of gene escape associated with transgenic soybeans in China and maize in Mexicoto their wild relatives are different because China and Mexico are the centers of diversity ofthe respective species.Additionally, transgenic crops may have an effect on a non-target organism. Evidence hasshown that the lethal dose (LD50) of Bt varieties for beneficial insects, such as bees andladybugs, is far higher when such insects are exposed to fields of these transgenic varieties.Some studies have also reported the safety levels of Bt varieties for the monarch butterfly(Tabashnik, 1994; Tang, 1996).A study under the auspices of the European Union addressing the environmental impactscaused by cultivation of GM crops was conducted for 15 years (1985-2000) involving 400public research institutions and reached the following conclusion: "Our research shows that,according to standard risk assessments, GM organisms and their products do not presentrisks to human health or the environment. In fact, the use of more precise technology andconducting the most accurate analysis possible during the regulatory process associatedwith these varieties make these products even more secure than their conventional forms(European Union, 1999 – available cropsintheEUBIO4EU.pdf).5. Biosafety regulationsThe need for official regulation of genetically modified organisms became more evident inthe mid-1980s, when biotechnology companies sought permission to perform research ongenetically modified organisms.Currently, implementation of biosafety rules is determined on a case-by-case basis aroundthe world based on technical and scientific data, with transparent decision-making andconsistency, building public confidence. There is no international standard established, andeach country is responsible for creating its own regulations for research, trade, production,transport, storage and disposal.5.1 Regulatory agenciesField testing of the first transgenic plants began in the early 1980s. To date, there have beenmore than 25,000 field tests performed worldwide, half of which have been in the UnitedStates and Canada. In South America, the greatest number of releases occurred in Argentina.The commercialization of GM crops began in 1994, with tomatoes genetically engineered byCalgene. Transgenic varieties of soybean, maize, cotton, canola and papaya, among othercrops, already represent a significant share of agriculture in the United States, Brazil,Canada, and Argentina. These varieties have been modified for resistance to insects andviruses and tolerance to herbicides. Field testing and laboratory evaluation of GMOs havebeen performed by regulatory agencies in each country to evaluate the risks of the GMOs tohuman and animal health and the environment.In the United States, the agencies that examine the safety of genetically modified varietiesinclude the Environmental Protection Agency (EPA), the Food and Drug Administration(FDA), and the Animal and Plant Health Inspection Service (APHIS) of the United StatesDepartment of Agriculture (USDA).www.intechopen.com
Biosafety and Detection of Genetically Modified Organisms433The USDA-APHIS regulates field tests of both plants and genetically modifiedmicroorganisms. This is the agency that reviews the licensing procedures for field testing byindustry, universities and nongovernmental organizations (NGOs). The processes related tothe agricultural and environmental safety of herbicide organisms, such as RoundupReadyTM (RR) soybeans, are also reviewed by USDA-APHIS.The FDA evaluates the safety and nutritional aspects of genetically modified varieties thatare used for human food and feed for animals. The FDA guidelines are based on the factthat food derived from GMOs must meet the same rigorous safety standards required forconventional foods.The EPA is responsible for ensuring the safety of GMOs and varieties that produce pesticideelements and chemical and biological substances for distribution, consumption and trade.Under U.S. law, the jurisdiction of the EPA is limited to pesticides. For example, a plant thathas been genetically modified to resist insects falls within its jurisdiction, but not a plantmodified to resist drought. Plant resistance to a pest is under the authority of the EPAbecause the plant produces a substance that acts as a pesticide. In contrast, droughtresistance may be due to factors such as deeper roots, and this transgenic plant would besubject to regulation by the USDA-APHIS.With respect to pest-resistant varieties, the EPA has four categories o
21 Biosafety and Detection of Genetically Modified Organisms Juliano Lino Ferreira 1, Geraldo Magela de Almeida Cançado 1, Aluízio Borém 2, Wellington Silva Gomes 2 and Tesfahun Alemu Setotaw 1 1Plant Biotechnology Laboratory, Ag ricultural Research Agency of Minas Gerais - EPAMIG, Caldas MG, 2Department of
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