- Количество слайдов: 30
Environmental and Biosafety issues in modern Biotechnology Dr Veena Chhotray, IAS Senior Fellow, TERI 6 th February, 2006
BIOSAFETY ‘Biosafety’ means the need to protect human and animal health and environment from the possible adverse effects of the products of modern biotechnology
International Evolution n Environmentalism emerged as a distinct development in the last forty years. Ø Emergence of “pressure groups” in the sixties Ø First Earth Day (1970) Ø The United Nations Conference on the Human Environment and Development (1972) Ø The Brundtland Report: our Common Future (1987) Ø The Rio Earth Summit (1992) Ø Convention on Biodiversity (CBD)  Ø Cartagena Protocol on Biosafety (CPB) 
Convention of Biodiversity (CBD)  n n n Focus: conservation and sustainable use of biodiversity Recognized the potential of modern biotechnology for human well being Took cognizance that modern biotechnology could have serious effects on environment and health Article 8(g) emphasized the need to regulate the risks associated with the use of LMOS. Article 19(3) set the stage for a legally binding international instrument about biosafety.
The Cartagena Protocol on Biosafety (CPB) n n n Entered into force on 29 th December 1993 Focus on transboundary movement of the LMOS. Seeks to lay down an internationally acceptable framework to provide for an adequate level of protection against the possible adverse affects of LMOS on biodiversity and human health.
Basic Premises of CPB n n n “Advance Informed Agreement” between Parties (AIA) Decision on the basis of scientific risk assessment Precautionary Principle
How is Genetic Engineering (GE) different from conventional breeding (CB)? n n Combining DNA in new combinations and introducing it into a new organism are the GE tools. Main differences between CB and GE Ø Ability to move across sexual barriers Ø Amount of change: a specific gene embodying a particular trait or thousands of genes embodying desirable and undesirable traits Ø Occurrence of change in one or several generations.
Genetic engineering: Recombinant DNA technology
Is GE inherently unsafe? n n Two diametrically opposite trends of thought US-Canada n No new risks associated with GM crops n New regulations not considered necessary n Safety assessments Ø ‘Product’ rather than ‘process’ based Ø In comparison and contrast to their ‘familiarity’ and ‘substantial’ equivalence to conventional crops
…Is GE inherently unsafe? n EU n n n Safety assessment n n n GE crops considered new and special Existing legislation not considered sufficient Process based Principle of ‘substantial equivalence’ beginning rather than the end Adoption of ‘Precautionary Principle’ as guide
…. Is GE inherently unsafe? n n GE technology carries certain inherent unpredictability Some facts n Isolation of a gene from its natural environment and integration into entirely different organism n Possible transgenic instability due to triggering of the inbuilt defense mechanisms of the host organism leading to inactivation or silencing of foreign genes.
…. Is GE inherently unsafe? n Possibilities of integration of foreign gene at a site predisposed to silencing of genes (position effect). Ø Variance in the levels of expression of the transgene in different environmental conditions (heat, humidity, light…. . ) Ø Possibilities of silencing of genes arising in subsequent generations Case by case sound scientific assessment is of utmost significance
Biosafety issues in transgenic crops n n Relate to environmental, human and animal health consequences Both can have short and long term implications Biosafety risks involve the entire spectrum of biodiversity A universal ‘true for all’ approach may not be applicable Risks Known Probability Unknown Probability • Rigorous Scientific Assessment • Risk Mitigation • Precautionary Principle
. . Biosafety issues in transgenic crops Biosafety concerns arise from: n n n Horizontal gene transfer Genetic contamination Transfer of allergens and toxins from one life form to another and creation of new toxins and allergenic compounds
. . Biosafety issues in transgenic crops Main - Concerns Ø Development of aggressive weeds/ wild relatives by transfer of transgenic traits Ø Erosion of land races/wild relatives by genetic pollution in centres of origin/ diversity Ø Harm to the non-target organisms Ø Development of pest resistance by prolonged use Ø Monoculture and limitations to farmers’ choice in crop management Ø Hazard to human and animal health by transfer of toxins and allergens and by creation of new toxins and allergenic compounds
. . Biosafety issues in transgenic crops Assessment n n n GE venturing into an unknown biological territory ASILOMAR Conference (1975): No research till safety guidelines in place Initially, focus on laboratory safety procedures Wider definition of biosafety with possibilities of commercialization of GM products The broad format of biosafety parametres essentially the same in all regulations
. . Biosafety issues in transgenic crops Two main stages: 1. 2. Laboratory/green house stage Confined Trial Stage IMPORTANT Prevention of the spread of genetically engineered material outside lab/field
Laboratory/green house stage n. Different biosafety levels as per the degree of risk involved n. Two methods of containment v. Physical v. Biological
Confined Trial Stage A confined trial is a small scale release of a transgenic plant species for research purposes conducted under conditions that prevent spread of the organism and mitigate its impact on the surrounding environment Objective is to collect data to evaluate the crops’ performance
Focus on Risk Mitigation Risk mitigation – the terms and conditions that are necessary to conduct the trial safely. n n n Prevent Gene Flow Prevent entry of GMOs into food chain Prevent Persistence of GMOs in the field
Bio-pharmaceutical therapeutics Biosafety risk n Survival, multiplication and dissemination of GMOs in contained/ open environment n Interaction of GMOs with biological systems n Routes of dissemination: physical; biological Risk depends upon n Nature of organism invovled n Extent of use of LMOs n End product LMO or not?
…Bio-pharmaceutical therapeutics Risk categorization of micro organisms: determining factors n Capability to cause disease n Hazard to laboratory workers n Risk of spread to community n Availability of effective treatment Health risks n Toxigenicity Pathogenicity n Allergenicity Antibiotic resistance
. . Bio-pharmaceutical therapeutics Environmental risks n Outcrossing between GMOs and pathogens n Negative effects on populations of non target organisms Risk assessment n Access n Expression n Damage Risk management and communication n Physical n Biological
GM foods: need for safety assessment n n n Expressed proteins generally not a part of regular food supply Food complex mixtures e. g. nutrients, antinutrients and natural toxins Directly enter human system Assume different forms Involve storage, processing, transportation
. . Safety assessment of GM foods comprise Guidelines by Codex Alimentarius Commission n Assessment of possible allergenicity n Assessment of possible toxicity n Compositional analysis of key components n Food processing n Nutritional modification
…. GM foods: Allergenicity; Toxicity Allergy It is a hypersensitive reaction initiated by immunologic mechanisms caused by specific substances called allergens. Assessment n Is the gene source allergenic? n Expression level of introduced gene n Unintended effect n Digestibility and heat stability Toxicity n n n New proteins as a result of intended modification Unintended new proteins as a result of the modification Natural constituents beyond their level of normal variation
…. GM foods: nutritional aspects; unintended effects n n Intended and unintended changes in nutrient levels Bioavailability of nutrients, stability and processing Presence and effect of anti-nutrients Impact of individual changes on overall nutritional profile Unintended effects Random integration of transgenes n Insertional mutagenesis n Disruption of gene functions n Production of new proteins n Changes in o Phenotype Metabolites o Enzymes Toxins o Genotype
Concluding Note…… n n n n Biosafety is integral to modern biotechnology The adoption of modern biotech products needs to be balanced with adequate biosafety safeguards Case by case scientific risk assessment and cost benefit analysis Greater acceptance of health care applications Need based adoption in GM crops and foods Participation of various stakeholders Dissemination of knowledge and information