Introduction
Responses to key issues raised by anti-GMO activists
1. African regulators don’t have adequate expertise to effectively assess the safety of GM products in the continent.
All Biosafety Regulatory bodies in African countries involved in biotechnology have scientific advisory committees comprised of highly qualified scientists trained in relevant areas of biotechnology/biosafety in renowned universities in Africa and overseas. These committees review all biotech applications in their countries and make recommendations for the regulatory bodies to make informed decisions.
2. African scientists do not have adequate equipment to fully assess safety of GM products.
South Africa and Burkina Faso do have laboratories and equipment for safe production of GM products such as Bt seeds. Moreover they network with their international colleagues and the global scientific community to solve any emerging technical challenge.
3. The adoption of modern biotechnology in African countries violated the provisions of the Cartagena protocol that requires public information and participation in decision making. In African countries like Burkina Faso there was no open debate before going into biotechnology.
The adoption of modern biotechnology in Africa has followed closely the provisions of the Cartagena protocol. Every country has its own history of technology adoption and for all new technologies; it has never been so easy. In a country like Burkina Faso, biotechnology was found to be the only option to solve pest resistance issues that were undermining the cotton sector. Producers urged the political leaders to come up with the best solution. Burkina Faso started confined trials in 2003 while implementing the necessary regulations; the Cartagena protocol was ratified by the county in the same year (2003) and a national biosafety committee was established in 2004. A national law was adopted by the Parliament in 2006 well before Bt cotton was commercially released in 2009. Although biotechnology was adopted as an urgent solution to save the cotton sector, its implementation complied adequately with the national and international regulations.
4. Biotechnology adoption in Africa is more about a deal between the government of the USA and African States than a real need in the field. There are more suitable, cheaper and environment-friendly crop production techniques for African producers.
Africa has been implementing so-called cheap and environment-friendly crop production for decades and yet the continent is one of the most crippled by food insecurity. Africa needs today sustainable and more effective solutions to boost food production and no technology that has proven efficient on another continent should be neglected, including biotechnology. Biotechnology is not certainly a panacea but it can greatly help to solve some of the critical agricultural challenges in Africa, including pest pressure, droughts, and climate change.
5. Monsanto is bribing a wide range of stakeholders to impose its technology on African producers.
Monsanto is not the only industry operating in Africa in the biotechnology sector. European firms like Bayer and even Chinese multinationals are present especially in Cameroon and Sudan, respectively. It is also important to understand that farmers have generally strong associations in African countries and their voices are among the most heard by politicians; so no bribed politician can impose a technology to them if they do not see benefit from it.
6. A study in Russia showed that eating GMOs could affect fertility in third generation.
This study by the Russian biologist Alexey V. Surov on hamsters has not been acknowledged by the international scientific community, reliable studies from The National Academy of Science (USA), FAO, the European Union Comission Directorate General for Research the International Council for Science the American Medical Association etc… have proved that all commercialized GM products are as safe as their non-GM counterparts.
7. A study by Seralini, a French scientist, showed that GMO consumption caused cancer in laboratory mice so the same could happen to human beings.
Same as above. It was unanimously recognized that Seralini’s study did not follow the required scientific protocol needed to produce reliable data and was therefore found inconclusive.
8. Studies commissioned by the World Health Organization recently concluded that the Roundup Ready active ingredient, glyphosate, is potentially carcinogenic. So eating crops like Round-up Ready maize, cotton oil, and soybeans could cause cancer.
People around the world have been eating GMO for two decades now and no reliably documented human or animal safety issues have been reported since biotech crops were first grown in 1996. All biotech crops go through thorough extensive testing before they are approved for commercial release to farmers and consumers. Researchers conduct more rigorous studies on biotech crops than those conducted for conventional crops to determine the safety of biotech crops. Regulatory and scientific agencies worldwide including the Food and Agricultural Organization (FAO) and the World Health Organization (WHO) who have reviewed the studies have confirmed the safety of biotech crops currently on the market. GM crops are studied for potential changes in nutritional composition, toxicity and allergenicity. The studies conducted ensure that biotech crops are as safe as their non-GM counterpart for human/animal consumption. Glyphosate also has been extensively tested and is one of the least toxic of all herbicides. It is considerably less acutely toxic than commonly consumed chemicals such as nicotine, caffeine, and tylenol, and has been found to be non-carcinogenic by U.S. and European agencies.
9. Glyphosate destroys soils and all useful soil micro-organisms. So in the long term, it will degrade all soils and impoverish producers.
Crop rotation is recommended just like in conventional or organic farming to preserve land fertility. Alternative herbicides that would be used instead of glyphosate have equal or greater toxicities to the land and environment, and weed control by cultivation rather than herbicide use results in increased soil erosion.
10. Studies showed that the Bt toxin that protects Bt crops is present in all Bt products so Bt products are not safe food and feed.
The toxin produced by the bacterium Bacillus thuringiensis (Bt) is very highly specific for certain types of insects, and not even all kinds of insects. It does not affect other types of animals (birds, fish, mammals) or humans. It is also used by organic farmers in spray form to control pests in their fields. Studies from reliable institutions such as The National Academy of Science (USA), FAO, European Union, the American Medical Association etc. have shown that GM food is as safe as non-GM food.
11. Most safety studies were done by the industry itself so these studies are not fully reliable. There are very few independent studies.
The list of reliable institutions that carried out thorough study on safety of GM food is actually long and includes:
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FAO,
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The National Academy of Science (USA)
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European Union
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The World Health Organization
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American Medical Association
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The Royal society of Medicine
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American Association for the Advancement of Science etc.
12. Biotechnology is a clever way the industry has come up with to control the seed production around the world and make producers more dependent.
Agricultural biotechnology is just a tool used to overcome some of the most critical challenges e.g. pest pressure, recurrent droughts etc. faced by farmers in some countries. Countries freely choose to adopt or not adopt biotechnology. Even in countries that allow GM production, farmers do not have to grow GM crops. If they prefer, they can continue to grow the varieties they used in the past. So far countries that have adopted modern biotechnologies are deriving benefits in terms of increases in yield and improved incomes.
13. GM seeds are not a solution to pest or weed control because pests and weed are developing resistance and the situation may become worse. Natural pesticides are the best solution.
Natural pesticides
African countries have tried organic farming with natural pesticides for decades but the continent is still suffering from lack of food and malnutrition.
Insect resistance
Insect resistance is a natural evolutionary process enhanced by repeated exposure of the pest to high toxins. It can arise due to the widespread use of GM crops, but also with the widespread use of any chemical pesticide on conventionally bred crops (natural or chemical). Insect resistance to Bt can be slowed down by growing non-Bt crops (refugia) together with Bt crops, so that the resistant insects mate with susceptible ones. The planting of refugia is required in all countries utilizing Bt crops. Other strategies that can slow down insect resistance include: stacking or pyramiding toxins that are distinct from each other, sterile moth releases, crop rotation and use of trap crops. Integrated pest management should not be neglected because no single method is sufficient.
Emergence of minor or secondary pests as key pests
Application of chemical pesticides typically kills all insects, including primary pests, secondary pests and beneficial insects. Bt is highly specific and does not kill all insects. When Bt crops are grown, the reduced use of chemical pesticides that would have killed the secondary pest can result in increased populations of secondary pests, as has occurred for a cotton pest in China. Integrated pest management practices such as crop rotation, biological control agents not targeted by the transgenes, tillage, intercropping, trap cropping should not be neglected by farmers.
Glyphosate resistant weeds have been reported in U.S, Australia, Malaysia, East Asia and Chile. Emergence of glyphosate resistant weeds can result from selection pressure from repeated glyphosate applications. The rare individuals that are resistant are the ones that are able to survive and produce seeds. Integrated weed management practices are important in managing evolution of herbicide resistant weeds. Such practices include: growing herbicide tolerant crops in rotation with conventional crops, tillage and use of other herbicides.
14. Neither modern biotechnology nor conventional agriculture is sustainable. There are better methods with a good combination of organic and no-tillage farming.
No farming method is a standalone solution or a panacea to agricultural challenges today. Each method could be a specific response to a specific situation. It is all about finding the best solutions to food and nutrition challenges in each country.
15. Biotechnology is more beneficial to big farmers not for smallholder producers. GMO producers will soon control most of the fertile lands around the globe and smallholder producers will have to give up their small lands and become just farm workers for large scale producers. Biotechnology is not a pro-poor technology.
What we have seen so far in Burkina is just the opposite. Almost all Bt cotton farmers are smallholder producers and their income keeps increasing since the commercial release of Bt cotton in 2009. The situation is also different globally because in 2014, 18 million farmers benefited from growing biotechnology crops of which 90% were small resource-poor farmers. In addition in Sudan, biotechnology cotton is being grown by small scale farmers..
16. It is morally unacceptable to insert animal genes to plants. These 2 worlds are separated by nature, why should we try to mix them?
All new technologies can raise ethical and moral questions. Some global moral authorities have recognized the importance of biotechnology as a tool that could help alleviate food insecurity and poverty around the world. “It is legitimate for humans, with the correct attitude, to intervene in nature and make modifications,” Cardinal Peter Turkson, President of the Pontifical Council for Justice and Peace told a room of about 1,000 people attending the World Food Prize symposium in downtown Des Moines. “The human person does not commit an illicit act … when he intervenes to modify some of their characteristics,” even at the genomic level, for food production. Citing Pope John Paul II, Turkson said adverse climate change has affected food production in poor countries, “and the findings of science must be put to use in order to ensure a high productivity of land.” In addition, farmers are always free to choose whether they will grow GM crops or not. In Burkina Faso, there are three groups of cotton growers: Bt cotton farmers who are the larger group, conventional growers and organic farmers.
17. With Bt cotton the quality of the lint and the length of the fiber are lower.
This situation happened in Burkina Faso just because Bt seeds were not backcrossed enough before commercial release. The Bt trait was not incorporated into the very best lines. The National Seed Company and Monsanto are aware of the issue and are currently working to fix this. Other Bt cotton varieties have excellent fiber quality that equal or exceed conventional varieties.
GM Food Safety Q&A
1. Are there risks with eating any food?
Virtually every food we eat possess risk. Based on statistics by the World Health Organization, the primary risk associated with eating food is illness due to microbial contaminants, such as food-borne viruses and bacteria. WHO estimates that foodborne and waterborne diarrheal diseases taken together kill about 2.2 million people annually, 1.9 million of them children. The safety of the chemicals in food, both natural and man-made, is also an important consideration. Some are natural plant chemicals that may be toxic because they are produced by the plants to protect them against insects and other herbivores. For example, solanine, a glycoalkoloid in potatoes, is toxic to humans but naturally protects the plant with its fungicidal and pesticidal properties. Others may be unintentional contaminants such as pesticide residues. International bodies such as the Codex Alimentarius Commission, give guidelines on the maximum residue limits for pesticides in food that are considered safe to eat (http://www.codexalimentarius.net/pestres/data/index.html).
2. What is considered to be safe food?
The World Health Organization/Food and Agriculture Organization (FAO) defines food to be safe if there is reasonable certainty that no harm will result from consumption under the anticipated conditions of use (CAC/GL45-2003). The FAO suggests that safety assessments should provide assurance, in the light of the best available scientific knowledge, that the food does not cause harm when prepared, used and/or eaten according to its intended use. The absolute safety of a food or an ingredient can never be guaranteed. However, with appropriate precautions during production, manufacture into products, and distribution, risk can be kept to an absolute minimum that is generally acceptable to consumers.
3. Are there specific food safety concerns associated with GM foods?
Genetically modified foods are not inherently less safe than their traditional counterparts. This conclusion has been reached by WHO, FAO and all National Academies of Science and established scientific authorities from around the world who have investigated this question, including countries from Europe, Asia, North and South America (e.g., International Council for Science; English, French, Italian, U.S., Mexican, Brazilian, Indian and Chinese Academies of Sciences).Nevertheless, due to lack of past experience with GM foods and concerns about novel technologies, these foods have been subjected to rigorous safety assessment procedures that are not generally applied to traditional foods. The determination of the safety of GM foods relies on a broad comparison of the properties of the GM crop to those of its conventional counterpart with a known history of safe use. The most common food safety concerns raised about GM foods include: Is it dangerous to eat foreign DNA? Can genes from GM foods be transferred to people? What is the possibility that GM foods will be allergenic? What is the possibility of novel toxins and anti-nutrients being produced in GM foods? Is there risk associated with resistance genes included in GM foods? These questions are discussed in the following sections.
4. Is it dangerous to eat foreign DNA?
All the food that we eat is derived from living organisms such as plants and animals; all living organisms contain genes which are made up of DNA. The human digestive system degrades all DNA into small fragments, whether it is from GM or conventional food. Numerous experimental studies with livestock have shown that DNA fragments or proteins derived from GM plants have not been detected in tissues, fluids or edible products of farm animals. “Therefore if one eats DNA in a GM food or a conventional food, it will not change their own DNA or that of their children” (European Food Safety Authority (EFSA), 2007; http://www.efsa.europa.eu/EFSA/Statement/EFSA_statement_DNA_proteins_gastroint.
5. What is the possibility that GM foods will be allergenic?
If a new protein is introduced into a potential GM crop, its allergenic properties must be tested to ensure safety. A series of tests are performed on the protein produced by the introduced gene to identify potential allergenic effects prior to product approval. Tests are also done to be sure that the levels of naturally occurring allergens are not increased in the GM food. If a conventional food that already contains allergens is genetically engineered, the GM food will also contain those allergens, unless specific steps are taken to remove the allergens. For example, soy naturally contains proteins that cause an allergic reaction in some people. Unless these specific proteins are removed, they will also be found in GM soy varieties.
6. What is the possibility of novel toxins and antinutrients being produced in GM foods?
All substances, whether natural or human-made, are potentially toxic depending on the dose. Substances classified as toxins are those that can be harmful to health at typical levels of exposure. For GM products, there is concern that a new toxic substance will be introduced or the levels of toxic substances already present in the crop might be increased. The products of the new gene are tested to ensure that they are readily digested and are not toxic using simulated mammalian conditions and animal testing as needed. Levels of the naturally occurring toxins are also measured to ensure that they are not elevated above their natural levels. The GM crop is also tested to ensure that nutritional composition has not been significantly altered.
7. What is the risk associated with resistance genes in GM foods?
Antibiotic resistance marker (ARM) genes are commonly used to assist in the process of genetically engineering plants. There has been concern about the effect of these genes on human health and safety, if such genes present in GM foods were able to transfer to microorganisms in the human digestive tract. This question has been studied extensively by many groups (e.g., http://www.efsa.europa.eu/en/news/news/gmo070413.htm).
The DNA in ARM genes are not any different from other DNA present in plants and animals. It is digested and processed in the gastro-intestinal tract just like DNA from any other source. When expressed in plant cells, the commonly used ARM genes have been shown to produce proteins that are digested in a similar way to other thousands of dietary proteins that humans consume every day. In addition, ARM proteins are frequently produced by human intestinal bacteria and thus humans have been exposed to these proteins throughout history.
Therefore, it has been concluded that ARM genes themselves and the proteins they express, as with other genes and proteins in foods and feed do not pose risks to the health of humans or animals. The European Food Safety Authority has recently reaffirmed that the two antibiotic resistance marker genes, npt II and aadA, used for GM plants pose no threat to humans or the environment (EFSA, 2007).It is also important to note that the antibiotic resistance genes currently present in GM foods code for resistance to antibiotics that are not widely used in human medicine, because resistance to them is already widespread. For example, the npt II gene confers resistance to neomycin, kanamycin and other antibiotics that are not in clinical use any more.
It is expected that in the future, as genetic engineering techniques evolve, antibiotic resistance genes will not be present in GM foods because they will either have been removed during development or have been replaced by other types of marker genes.
8. How is the safety of GM foods assessed?
Internationally harmonized evaluation strategies have been developed to test for the safety of foods derived from genetically modified organisms (GMOs). GM- derived products, be they food, food ingredients, or foods produced by GM microorganisms, undergo more stringent safety assessment procedures than is required for non-GM foods.
The approach taken is based on the concept of Substantial Equivalence (SE). SE asks whether the GM food is as safe as its traditional counterpart. (See section below for more details). On a case-by-case basis, toxicological, and nutritional investigations may be required before commercialization.
The comparator approach should consider agronomic, morphological, genetic and compositional aspects in order to make an objective assessment. Particular attention should be paid to the choice of comparator, the design of field trials, and statistical analysis of the generated data in order to obtain good comparative data. The GM crop and the comparator should be grown in the same environmental conditions to avoid genotypic and phenotypic differences not related to the transformation process (Herman et al., 2007).An assessment of GM crops looks at the following key factors:
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Molecular characterization of the new genetic material and transformation process
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Phenotypic characterization of the new product
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Safety of new products
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Occurrence and implications of unintended effects
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Pathogenic, toxicity and anti-nutrient effect
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Allergenicity of new products
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Role of the new food in the diet
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Influence of food processing
9. What kinds of information should be included in a food safety assessment dossier?
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Description of the Recombinant-DNA Plant
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Identification of the crop.
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Name of the transformation event(s).
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Purpose of the modification, sufficient to aid in understanding the nature of the food being submitted for safety assessment.
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Description of the Host Plant and its Use as Food
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Common or usual name; scientific name and, taxonomic classification.
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History of cultivation and development through breeding, in particular identifying traits that may adversely impact on human health.
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Information on the host plant’s genotype and phenotype relevant to its safety, including any known toxicity or allergenicity.
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History of safe use as a food.
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How plant is typically cultivated, transported and stored.
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Information on special processing required to make the plant safe to eat.
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Part of the plant used as a food source.
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Important macro- or micro-nutrients the food contributes to the diet.
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If the food is important to particular subgroups of the population.
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Description of the Donor Organisms
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Common and scientific name.
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Taxonomic classification.
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Information about the natural history of the organism as concerns human health.
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Information on naturally occurring toxins, anti-nutrients and allergens.
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In case a microorganism is the donor organism, additional information on human pathogenicity and the relationship to known human pathogens.
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Information on the past and present use, if any, in the food supply and exposure route(s) other than intended food use (e.g. possible presence as contaminants).
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Description of the Genetic Modification(s)
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Information on the specific method used for the modification.
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Information on the DNA used to modify the plant including the source (e.g., plant, microbial, viral, synthetic), identity and expected function in the plant.
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Details of all genetic components of the vector used to produce or process DNA for transformation of the host organism.
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Information on all the genetic components including marker genes, regulatory and other elements affecting the function of the DNA.
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Location and orientation of the sequence in the final vector/construct and function.
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Characterization of the Genetic Modification(s)
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Information on the DNA insertions into the plant genome including:
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characterization and description of the inserted genetic material.
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number of insertion sites.
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organization of the inserted genetic material at each insertion site including copy number.
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sequence data of the inserted material and of the flanking regions bordering the site of insertion, sufficient to identify substance (s) expressed as a consequence of the insertion.
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identification of any open reading frames within the inserted DNA or created by the insertions with contiguous plant genomic DNA including those that could result in fusion proteins.
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For any expressed substances in the rDNA plant the information to be provided include:
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gene product(s) (e.g. a protein or an untranslated RNA).
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gene product(s)’ function.
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phenotypic description of the new trait(s).
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level and site of expression of the expressed gene product(s) in the plant, and the levels of its metabolites in the edible portions.
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amount of the target gene product(s), where possible, if the function of the expressed sequence(s)/gene(s) is to alter the accumulation of a specific endogenous mRNA or protein.
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information on deliberate modifications made to the amino acid sequence of the expressed protein result in changes in its post-translational modification or affect sites critical for its structure or function.
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Additional information to be provided:
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demonstrate whether the arrangement of the genetic material used for insertion has been conserved.
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show whether the intended effect of the modification has been achieved and that all expressed traits are expressed and inherited in a manner that is stable through several generations consistent with laws of inheritance.
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demonstrate newly expressed trait(s) are expressed as expected in the appropriate tissues in a manner and at levels that are consistent with the associated regulatory sequences driving the expression of the corresponding gene.
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any evidence to suggest that one or several genes in the host plant has been affected by the transformation process.
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confirm the identity and expression pattern of any new fusion proteins.
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may be necessary to examine the inheritance of the DNA insert itself or the expression of the corresponding RNA if the phenotypic characteristics cannot be measured.
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Compositional Analyses of Key Components
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Proximate composition including ash, moisture content, crude protein, crude fat, and various carbohydrate.
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Protein amino acid profile.
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Quantitative and qualitative composition of total lipids, i.e., saponifiable and nonsaponifiable components, complete fatty acid profile, phospholipids, sterols, cyclic fatty acids and known toxic fatty acids.
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Composition of the carbohydrate fraction e.g., sugars, starches, chitin, tannins, nonstarch polysaccharides and lignin.
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Qualitative and quantitative composition of micronutrients, i.e., significant vitamin and mineral analysis.
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Presence of naturally occurring or adventitious anti-nutritional factors e.g., phytates, trypsin inhibitors, etc.
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Predictable secondary metabolites, physiologically active (bioactive) substances, other detected substances.
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Assessment of Possible Toxicity
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Indicate if the donor organism(s) is a known source of toxins.
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Amino acid sequence homology comparison of the newly expressed protein and known protein toxins and anti-nutrients.
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Demonstrate the susceptibility of each newly expressed protein to pepsin digestion.
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Where a host other than the transgenic plant is used to produce sufficient quantities of the newly expressed protein for toxicological analyses, demonstrate the structural, functional and biochemical equivalence of the non-plant expressed protein with the plant expressed protein.
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Oral toxicity study(s) completed for newly expressed proteins.
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Assessment of Possible Allergenicity (Proteins)
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Indicate if the donor organism(s) is a known source of allergens.
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Amino acid sequence homology comparison of the newly expressed protein and known allergens.
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Demonstrate the susceptibility of each newly expressed protein to pepsin digestion.
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Where a host other than the transgenic plant is used to produce sufficient quantities of the newly expressed protein for toxicological analyses, demonstrate the structural, functional and biochemical equivalence of the non-plant expressed protein with the plant expressed protein.
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For those proteins that originate from a source known to be allergenic, or have sequence homology with a known allergen, additional immunological assays be warranted.
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GM crops and Biodiversity: Q&A
1. What is biodiversity and what are people concerned about in relation to the widespread cultivation of GM crops?
Biodiversity refers to the number of different species that are present in a given location, along with the numbers of individuals in each species and the genetic variability within the species. More formally, biodiversity is defined as “the variability among living organisms from all sources, including, among others, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems” (Convention of Biological Diversity, 1992).
With the widespread planting of GM crops, the following questions have been asked frequently:
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Is it possible that GM crops cause the reduction of the number of species present or the amount of or genetic diversity within species (wild and/or cultivated)?
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Is it possible that local farmers stop planting traditional varieties because the GM crops provide useful traits (such as insect resistance) not available in the traditional varieties?
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Is it possible that the levels of genetic diversity in the traditional varieties will be reduced through hybridization with the GM crop?
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Is it possible that GM crops invade the natural environment and outcompete with native species?
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Is it possible that GM crops hybridize with wild relatives and make them more weedy or invasive?
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Is it possible that transgenes cause unintended (secondary) effects in natural populations?
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Is it possible that GM crops negatively affect species diversity in centres of diversity?
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Is it possible that GM crops negatively impact on non-target species?
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Is it possible that GM crops negatively impact on the non-living components of the release environment, damaging or polluting the air, soil or water?
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These concerns are discussed more fully below.
2. Could GM crops reduce species abundance or levels of genetic diversity within species?
This could happen only if GM crops: (1) replace crop varieties (including traditional land races), (2) invade natural habitats and outcompete with the wild species, (3) hybridize with wild relatives making them more invasive and allowing them to outcompete with other wild species, or (4) reduce the abundance of non-target species by producing compounds that reduce species numbers.
3. Could GM crops replace traditional crop varieties?
Traditional crop varieties, also called land races, are crops grown by subsistence farmers. They represent an intermediate stage of domestication between wild ancestors and modern varieties. Land races continue to change over time because of cross pollination and selection by farmers.
Will subsistence farmers stop planting traditional varieties because they perceive that GM crops are superior? Will the levels of genetic diversity in the traditional varieties be reduced through cross pollination with the GM crops?
To answer these concerns, there is a need to understand that:
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Farmers decide on what they will plant, based on what varieties are available to them and which ones they think will benefit them the most. For a farmer to plant a new variety, he needs to feel that his income and food security would be enhanced by growing that new variety.
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Most farmers know how to maintain the purity of traditional varieties if they so wish, even if grown in the same field or next to a field with other traditional and improved types1. This has been well documented.
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Small-holder farmers commonly share seeds, and usually plant mixed-seed populations or different varieties side by side to generate hybrid populations1. They have been doing this kind of informal breeding, either consciously or unconsciously since plants were first domesticated thousands of years ago.
Based on this, the possibility that GM varieties will replace traditional varieties is no different than that which has been posed by conventionally bred varieties for decades. While there are numerous instances where conventional varieties have replaced traditional ones, the change has generally been made by commercial farmers rather than subsistence farmers. Subsistence farmers rely on the diversity of their land races for yield stability from year to year, and they rarely have the resources necessary to grow modern varieties.
When a farmer saves seed from a cross between his or her traditional variety and another land race or improved variety, levels of genetic diversity can actually increase in his or her field rather than decrease. Genetic variability in a farmer’s field will only be reduced if he or she saves seed from only a very limited number of individuals each season, or he or she stops growing the traditional varieties altogether. But most subsistence farmers are interested in maintaining genetic diversity, not reducing it. Even when commercial varieties are grown for a cash crop, small-holder farmers frequently also plant traditional varieties, because these are preferred for household consumption. Thus, where there is a preference for traditional varieties, they will be maintained in communities.
In addition, genetic variety is valuable for plant breeders, who also maintain a gene bank of different varieties. There has been concern that the agronomic biodiversity of crops will decrease with the adoption of GM crops, because farmers will stop growing commercial varieties that do not have the new genetic improvements. However, the developers of GM crops have found that it is necessary to have the new genetic improvements in varieties that are best suited to different growing environments. For this reason, the GM traits are bred into numerous commercial varieties to ensure that farmers have access to the new genes in the varieties that are already best suited to their farms.
4. Could GM crops invade natural environments and outcompete with native species?
Whether a GM crop persists in the natural environment and competes with native species is dependent on the invasiveness of the crop species and how much the GM trait affects that invasiveness2. If the specific kind of trait that is expressed in a GM crop allows it to grow better in response to challenges from the local environment, it may provide an advantage in a non-agricultural situation. If this should happen, then the crop might outcompete with wild species, resulting in a decrease in biodiversity.
To date, the traits that have been engineered into GM crops (insect or virus resistance, herbicide tolerance, or compositional changes) have not noticeably enhanced the ability of these crops to invade unmanaged habitats and outcompete with wild species. However, all GM crop approvals include an evaluation on a case-by-case basis as to whether the new traits pose a potential threat to native species. Tiered risk assessment procedures have been developed to do this by evaluating the biology of the crop and the nature of the engineered trait.
5. Could GM crops hybridize with wild relatives making them more weedy or invasive?
If a GM crop is capable of crossing with a wild relative, then an engineered trait might be transferred to progeny of the wild relative. As was previously mentioned, whether an escaped transgene persists and has an impact on the abundance and competitiveness of a native species will be strongly associated with the nature of the new genes, and how invasive the recipient species was before the genes became incorporated.
If the new trait causes an advantage that allows the recipient populations to increase in number and spread more easily from the release environment, then other native species could be outcompeted. However, none of the traits that have been engineered into GM crops to date including insect, virus and herbicide resistance has the potential to enable a GM event to outcompete with wild species in nature.
With regard to agricultural practices, the new trait, such as herbicide tolerance, might allow wild species to become tolerant of the current measures used to control individuals in an agronomic field. If this should happen, then the wild species could present a new weed problem. If herbicide resistant weedy species become abundant, farmers will have to return to the method of weed control they used before the GM crop or utilize herbicides with different modes of action. Development of resistance to herbicides is not an issue specific to GM crops. Herbicide resistance evolves naturally in wild species even without the presence of GM crops. This resistance means farmers need to use diverse weed control measures to limit the development of herbicide resistance and to remove herbicide resistant weeds. The same diverse weed control practices are needed for the cultivation of GM crops3 Future GM crops will need to be evaluated on a case-by-case basis as to whether gene flow from them could significantly alter the competitiveness of native species. Tiered risk assessment approaches have been developed to assess these risks.
6. Could transgenes cause unintended (secondary) effects in natural populations?
These unplanned effects result from what are called “epistatic effects” or “pleiotropic effects”. Epistatic effects occur where the transgenes interact uniquely with the genes of the native species to produce an unexpected characteristic. Pleiotropic effects occur when the transgenes influence more than the target trait.
During the selection of events for commercial use, researchers compare the events to the conventional recipient to observe agronomic, phenotypic and compositional changes that might result from unintended changes. Events with different, unwanted phenotypes, composition or agronomic performance are eliminated during the selection process. The presence of unintended effects cannot not be completely excluded, but an effort is made to help ensure that the changes are those intended by the genetic improvement, and not just random changes to the plant genome.
7. Could GM crops negatively affect species diversity in “centres of diversity”?
A centre of diversity for a particular plant species is the area where a high degree of genetic variation of that species is found. The centre of diversity of a crop can also be its centre of origin. Centres of diversity are important storehouses of genes valuable for breeding new characteristics into crops.
Concerns have been raised that the planting of transgenic crops in “centres of species diversity” could result in losses of genetic variability. This could result from cross pollination between transgenic crops and close relatives that reduces the level of genetic diversity in the centre of diversity, or from transgenic crops outcompeting with wild types in centres of diversity and causing local varieties (and any rare genes they may contain) to become extinct.
An awareness and understanding of crop diversity and centres of diversity is used to help ensure that approved transgenic crops are not released and used in a way that will reduce genetic diversity in the agronomic and wild species. This genetic diversity is a valuable tool for plant breeders as it contains genes that could be used in future crop improvements.
Importantly, most crop progenitors are dispersed over a wide geographical range and their numbers are large, making it unlikely that wild type species will become extinct as a result of cultivation of transgenic crop varieties. Care is taken to recognise vulnerable and endangered species in release environments and to ensure that the impact on these is well understood and documented prior to approval for GM production. In addition, crops with multiple centres of diversity (wheat, sorghum, pearl millet, barley, pea, lentil, chickpea, flax, maize and lima bean), and those with no discernible centres of diversity (radish, cole crops and bottle gourd) have fewer concerns about loss of wild type diversity 4. Paradoxically, cross pollination between crops and wild species could result in higher levels of genetic diversity in the wild relatives when the genes of the wild species and the crop are blended together. As the hybrid population evolves, alleles may be lost, but the recipient population is likely to carry high levels of diversity for many generations.
Overall, the impact of cross pollination from a transgenic crop is fundamentally no different than that from conventionally bred crops, but the impact of the transgenes must be evaluated to fully understand and manage unwanted effect.
8. Could GM crops negatively impact on non-target species?
Non-target species are organisms which were not the intended targets, but that may be adversely affected by GM crops. These include pollinators, other beneficial species, soil organisms, endangered species, etc.
Indirect effects on non-target species are a concern for crops expressing compounds that protect them from pests, such as those that express Bt proteins. This concern applies equally to GM crops and the use of conventional pesticides.
The potential for negative impact on non-target organisms is assessed for all new GM crops before they are approved for commercial release and general use. The assessments are undertaken using a tiered approach that identifies when risk levels require further research. Risk assessment evaluates potential impact from direct exposure to gene products and from indirect exposure through feeding patterns and accumulation of gene products in the air, soil or water residues of the release environment.
Widespread commercial use of Bt genes for insect protection in GM crops has been carefully evaluated for non-target effects. From numerous field studies, the overall conclusion has been that there are no consistent differences in the composition of non-target organisms between GM and non-GM fields. Non-target studies have indicated that the growing of Bt cotton has an overall beneficial effect on biodiversity when compared to insecticide applications.
Future GM crops with novel pest protection genes must continue to be evaluated on a case- by-case basis before deployment, to assess the potential impact of these crops on non-target organisms. Tiered approaches have been developed to assess these risks and help to ensure that sufficient review is undertaken where potential risks are identified.
9. Could GM crops negatively impact on the non-living components of the release environment, damaging or polluting the air, soil or water?
All GM crops are reviewed to ensure that their use will not result in practices that could negatively impact on the non-living components of the release environment. This review looks at the nature of the new gene products and the agricultural management of the GM crops to compare the impact of these on the release environment, in comparison to the impact of the production of conventional crops. Crops that require more fertilizer or increased tillage may be responsible for increased water pollution or soil structural damage. This may be deemed less acceptable than conventional varieties, because these impacts on the abiotic components of the release environment can cause changes in the biodiversity of the area.
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