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Risk assessment: Bt corn MON810 Risk assessment: identifying and evaluating possible dangers predicting the chances the danger will occur assessing the extent of damage should the danger occur Risk or safety assessment: AO 8 science-based transparent case by case by transformation event Absence of scientific evidence is not construed to imply safety nor danger Risk assessment is revisited if new evidence is found Concept of substantial equivalence underlies risk assessment Substantial equivalence – identifying and evaluating danger by comparing Bt corn MON810 with a suitable comparator Comparator – isogenic line, average of trait among various varieties Sources of risks: 1.The host plant 2.The donor organisms 3.The transformation system 4.The inserted DNA 5.The genetic stability of the introduced trait 6. The inserted gene product ( expressed material) 7. Potential for toxicity of the expressed material Sources of risks: 8. The potential for allergenicity of the expressed material 9. The nutritional profile 10. Host plant – environmental assessment 11. Gene transfer to related plants 12. Gene transfer to unrelated organisms ( horizontal gene transfer) 13. Weediness potential 14. Secondary and non-target adverse effects 1.Host plant – corn safety of corn as food, as feed Is there a history of safe use? Does corn contain any antinutrient? Does it contain a native toxin or a native allergen? How is corn used? Does processing change its nutritional profile? 2. The donor organisms What are the donor organisms and their donated genes? Toxicity – Is/are the donor organisms toxic? Do they produce toxic substances? Are the donated gene products toxic? Could these new gene products interact to become toxic? 2. The donor organisms Allergenicity– Is/are the donor organisms allergens? Do they produce allergens? Are the donated gene products allergens? Could these new gene products interact with other usual substances to become allergenic? The transformation system Particle bombardment vs. Agrobacterium transformation Indirect effects due to the system: action of extraneous genes linked to the target trait, genomic modifications and rearrangements, pleiotropic effects Particle bombardment - riskier The inserted DNA How much is inserted? Only the target gene? How many copies? Target genes and selective markers e.g. antibiotic resistance genes? Where is the gene inserted? Can Insertion affect increased production of native allergens? native toxins? Genetic stability of introduced trait Emphasis on trait not DNA Is the trait expressed from generation to generation? Is the expression of the trait through generations the same? The expressed material/effects Characteristics of the expressed material: size of the protein, physicochemical characteristics, sequence, etc. Level & location of the protein – levels in target/edible tissue, Bt protein level in leaves – efficacy Bt protein level in grain – food safety Toxicological assessment Bt DNA insert – not issue Bt protein – expression in edible tissue, processing effects on Bt protein, history of protein, structure compared with known toxins, physicochemical properties – tolerance to heat, digestibility Bt corn – feeding studies Allergenicity Bt protein – source organism expression in edible tissue, immunoreactivity, sequence compared with known allergens, physicochemical properties – Heat/processing stability, digestibility, effect of pH Nutritional data Comparative analysis of Bt corn MON810 and isogenic lines and other commercial varieties The host plant – environmental Assessment Familiarity with corn – reproductive biology, occurrence of natural hybrids with wild relatives, interaction with other organisms, origin, presence of feral types, common pests and diseases Agricultural practices Horizontal gene transfer – examine data on presence of antibiotic resistance genes in Bt corn MON810 Effect on non-target organisms -Use of indicator species, field trials data – effects on population of beneficial arthropods Weediness potential Assess whether Bt gene affected the following: Dissemination of seeds Dormancy of seeds Competitiveness Agronomic characteristics e.g. time to maturity, disease and pest resistance Unintended effect Development of insect resistance to Bt protein Possibility of resistance development – 100% Mitigating measure – protect Bt technology Insect Resistance management – IRM Thank you for your kind attention