Controversies in Biotechnology PDF

Controversies in Biotechnology Controversies in Biotechnology ❑ Monarch butterfly controversy ❑ StarLinkTM controversy ❑ Poisonous potato controversy ❑ Mexican corn gene escape & gene flow ❑ Allergenicity ❑ Antibiotic resistance ❑ Terminator gene technology ❑ Stem cells therapy ❑...

Controversies in Biotechnology Controversies in Biotechnology ❑ Monarch butterfly controversy ❑ StarLinkTM controversy ❑ Poisonous potato controversy ❑ Mexican corn gene escape & gene flow ❑ Allergenicity ❑ Antibiotic resistance ❑ Terminator gene technology ❑ Stem cells therapy ❑ Empirical vs. moral debate ❑ Anything else? Controversies in Biotechnology ❑ Monarch butterfly controversy ❑ StarLinkTM controversy ❑ Poisonous potato controversy ❑ Mexican corn gene escape & gene flow ❑ Allergenicity ❑ Antibiotic resistance ❑ Terminator gene technology ❑ Stem cells therapy ❑ Empirical vs. moral debate ❑ Anything else? Gene Switching & GURTs (genetic use restriction technology) o Terminator technology o An ongoing discussion o Concerns: whether & how GURTs may impact indigenous peoples, local communities & small-holder farmers o A biotechnology-based gene switching is the use of genetic engineering to control specific genetic material (genes) in plants to achieve certain desired results o Targeted genes are controlled through “switch mechanisms.” o Mechanisms activate (turn on), deactivate (turn off), or adjust upward or downward specific plant functions Gene Switching & GURTs (genetic use restriction technology) o Controlling the “expression” of plant genes o Gene switching mechanisms may be established in response to an external trigger (e.g., rainfall, light patterns, chemistry), to activate the expression of genes at critical times, or in particular locations within the plant o Gene switching happens naturally* (e.g. seed germination) o Researchers are exploring the use of gene switching to allow a plant to express a gene only when it is needed o E.g. a drought tolerant plant will produce the gene for drought tolerance only when drought occurs; resource saving & optimization Gene Switching & GURTs (genetic use restriction technology) Other possible uses: 1. Development of sentinel plants = notify farmers when there is a nutrient deficiency or a pest infestation – enabling application of pesticides and/or fertilizers only when absolutely necessary 2. Targeted release of Bt or other pest protection mechanisms in a plant, help to further reduce potential development of pest resistance in conjunction with refuge IPM processes 3. Development of sterile progeny, further contributing to environmental risk management processes in centers of origin & other sensitive environments or areas with stringent biosafety frameworks Gene Switching & GURTs (genetic use restriction technology) o Biotechnology-based gene switching in plants describes a wide range of mechanisms to control plant gene expression for purposes beneficial to human beings and our environment o These technologies hold promise to more efficiently & effectively use traits in plants o In the case of the applications that result in plants that do not reproduce, the technology also offers an additional layer of biosafety protection as well as serving to protect research and development investments. StarLinkTM Corn Issue ✓ Started mid-Sept 2000 ✓ Aventis Crop Science Bt corn (StarLinkTM corn) ✓ Has Cry9c gene from B. thuringiensis subsp. tolworthi for resistance against European corn borer ✓ Approved by EPA for animal feed & industrial applications (non-food use & seed increase only) ✓ Not allowed for human food because protein from Cry9c has slow digestibility & no conclusive results yet on allergenicity potential ✓ EPA directs Aventis to facilitate proper disposal & prevent cross- pollination with regular corn ✓ Detected in taco shells by Kraft Foods & Taco Bell food chain ✓ ~ 1% contamination estimated StarLinkTM Corn Issue (2) ✓ October 2000, Aventis & EPA agreed to cancel the registration of StarLink ✓ Aventis bought back all of their StarLink seeds ✓ 51 alleged cases of allergenic reactions, only 28 of 51 were confirmed true by CDC ✓ An overblown issue since there were no significant health threats ✓ Lesson: any GE crop needs to be approved for food, feed & industrial use ✓ In the PHL and Asia in general, many food products are commercialized with no food tests (+other biochemical tests) StarLinkTM Corn Issue (3) ❑ EPA Scientific Advisory panel considered protein Cry9C a medium risk potential human allergen. ❑ Protein was slow to digest, suggesting a possible concern, but the protein’s a. a. sequence was not similar to known allergens therefore the likelihood of allergenicity is low ❑ Since Cry9C protein is only a small fraction of corn protein, probability that the protein would sensitize an individual is low. ❑ How did the contamination happen? StarLink grains are mixed with other varieties of corn through common milling companies. StarLinkTM Corn Issue (3) ❑ EPA Scientific Advisory panel considered protein Cry9C a medium risk potential human allergen. ❑ Protein was slow to digest, suggesting a possible concern, but the protein’s a. a. sequence was not similar to known allergens therefore the likelihood of allergenicity is low ❑ Since Cry9C protein is only a small fraction of corn protein, probability that the protein would sensitize an individual is low. ❑ How did the contamination happen? StarLink grains are mixed with other varieties of corn through common milling companies. Impact on farmers: need to meticulously clean all their equipment & other facilities (e.g. dryers, shellers, sacks, trucks, etc.) Processors/millers: segregation, labeling, cleanliness of equipment & other facilities will be very demanding & critical, etc. But, why demand all these if and when such products have been tested safe and substantially equivalent with their regular counterparts (non-GE products) except for the additional traits??? “Monarch Butterfly” ❑ EPA issue (Environmental Protection Agency) ❑ Several proteins from Bt are “endotoxins” to soe Lepidopteran species ❑ Milkweed *(Asclepias syriaca) – common host of MB; has some toxins too ❑ Hansen & Obrycki (1998) – potted milkweed plants near Bt & non-Bt corn fields; poster paper ❑ John Losey et al. (1999) – MB larvae fed with Bt pollen (lab); published in Science ❑ Illinois (2000) – field expt on black swallow tail butterfly (Wraight et al. 2000) ❑ Responsibility to review articles for partial info or misinformation; quality & quantity of research “GM Potato” ❑ Dr. Arpad Putzai (1998) experiment on potato aphid ❑ 5 rats fed with GM potato for 110 d ❑ GM potato has genes from snowdrop (Galanthus nivalis) bulb or South American jack beans (for lectins and Con A) ❑ Stunted rat growth & damaged immune system ❑ Lectins are resistant to digestion (toxic to insects, harmless to mammals) ❑ Trt: raw and cooked GM potato & non-GM potato ❑ Unreviewed results, unvalidated ❑ Dr. Putzai was suspended, GM potatoes were destroyed and pulled out*** ❑ Damage had been done – reputation questioned http://image.slidesharecdn.com/potatocontroversypresentation-120808033729-phpapp01/95/potato-controversy- presentation-5-728.jpg?cb=1344398105 “Mexican Corn Contamination” ❑ November 29, 2001 of Nature: 2 researchers at UC Berkeley reported presence of transgenic DNA constructs in native maize landraces grown in remote mountains in Oaxaca, Mexico ❑ Authors reported that it occurred as multiple introgression events, transgenic DNA constructs seemed re-assorted & introduced into different genomic backgrounds, possibly during transformation or recombination ❑ Introgression of transgenes, instability in the genome, & maintenance through generations, immediately raised interest & concern of scientific community, environmental protection organizations, & press ❑ transgenic maize was soon tagged as threat to existing maize biodiversity & to germplasm collection maintained ex-situ at CIMMYT ❑ But authors were not able to present solid empirical data to support their claims