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Lecture 24 Controversial transgenic plants: risks revisited Chapter 15 Neal Stewart

Lecture 24 Controversial transgenic plants: risks revisited Chapter 15 Neal Stewart. Discussion questions. Discuss controversies in the light of science and risks of transgenic plants—examples. What is the recipe for producing a controversy?

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Lecture 24 Controversial transgenic plants: risks revisited Chapter 15 Neal Stewart

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  1. Lecture 24 Controversial transgenic plants:risks revisitedChapter 15Neal Stewart

  2. Discussion questions • Discuss controversies in the light of science and risks of transgenic plants—examples. • What is the recipe for producing a controversy? • What are the 3 eras in plant biotechnology controversy? What happened to usher each in and out? • How can we critically examine risks and controversies?

  3. Mae-Wan Ho “Genetic engineering bio-technology is inherently hazardous… which will spell the end of humanity as we know it, and of the world at large.” Genetic Engineering: Dream or Nightmare 1999 p. 1

  4. NGOs and GMOs

  5. The Frankenstein paradigm:man controls (perverts) nature with science. Frankenfood

  6. The case of Arpad Pusztai’s transgenic potatoes • Insecticidal potatoes expressing a snowdrop lectin gene (codes for a sugar binding gene) • Not commercial product • Feeding study with rats—examined gut features • Compared transgenic and non-transgenic potatoes • Experimental design and controls? • Conclusion was that the transformation process itself or the promoter was responsible for the effect

  7. Pusztai’s potatoesSeries of events 1998 1999 1999-2000 • Small laboratory study promoted on national TV (in UK) by the author • Feeding frenzy by: • Popular media • NGOs • Scientific paper published in the Lancet (1999) 354: 1353-54. • Scientific resolution

  8. The case of the monarch and Bt cry1Ab corn pollen

  9. Monarch butterflySeries of events • Small laboratory study published in prestigious journal (Nature 399: 214)—a seemingly profound result. • Prestigious university (Cornell) makes press release. • Feeding frenzy by: • Popular media • NGOs • Increased scrutiny by: • Scientists • Regulators 1999 1999-2000 2001 • Scientific resolution

  10. Monarch butterfly What’s riskier? Broad spectrum pesticides or non-target effects? In October 2001 PNAS– 6 papers delineated the risk for monarchs. Exposure assumptions made by Losey et al. were not relevant--far off.

  11. Tiered approach—mainly non-targets What happens when these levels are used for risk quantification? Wilkinson et al. 2003 Trends Plant Sci 8: 208

  12. Illicit gene flow from, GM corn to Mexican landrace corn 2001 Corn belt The case of Quist and Chapela Oaxaca, Mexico Stewart (2004) Genetically Modified Planet Figure 5.1

  13. Transgenes from commercial corn to Mexican landrace corn Quist and Chapela 2001. Nature 414: 541-543. • CMV (sic) [CaMV] promoter DNA putatively found in maize landraces in Oaxaca, Mexico. • Claimed transgene introgression into landraces. • Used PCR (only) to make conclusions. • Study was thoroughly criticized by scientific community. • Paper “retracted*” in April 2002. *When a paper is really retracted, the authors’ acknowledge flawed science and officially retract the paper—it is as if it never existed. In this case, that did not happen. In 2002 the editor (for the first and only time when he essentially said he wish it would’ve never been published.

  14. What is introgression? • Gene flow • Hybridization • Introgressive hybridization Edgar Anderson 1949. “The permanent incorporation of genes from one set of differentiated populations (species, subspecies, races and so on) into another.” Stewart et al. (2003) Nature Reviews Genetics 4: 806

  15. Stewart et al. (2003) Nature Reviews Genetics 4: 806

  16. How many plant species introgress (interspcific)? Plant species that introgress: 100s? (165 proposed, 53 documented*) Plant species that hybridize: 10,000s All plant species 400,000-500,000 *From Rieseberg and Wendel 1993 Hybrid Zones and Evolutionary Processes Pp70-109 (Ed., Harrison)

  17. Weak PCR signals = A few transgenic kernels Even if results were valid, Introgression was not demonstrated.Better explanation would be spurious hybridization. They should have looked at inheritance and did Southerns And…Oriz-Garcia et al 2005 PNAS 102: 12238 No transgenic DNA was found in 153,746 Mexican landrace samples.

  18. Landrace maize saga continues • Piñeyro-Nelson, A. et al. Molecular Ecology 18: 750-761 (2009). Found evidence of 35S promoter in 2001 and 2004, but not 2002. Frequency of 35S in landrace maize= 1.1% by PCR and 0.89% using Southern blot analysis (but few samples were assayed using Southerns • Schoel, B. & Fagan, J. Mol. Ecol. 18, 4143-4144 (2009). Genetic ID: claimed that there was “insufficient evidence” for transgenes in landraces • Piñeyro-Nelson, A. et al. Mol. Ecol. 18, 4145-4150 (2009). • Counter-argued against Genetic ID.

  19. Who/what is Genetic ID? • “Global leader in GMO detection” according to the company website assessed April 13 2010. • Detection of transgenes using PCR and real-time PCR. • In Fairfield, Iowa. Also in Japan and Germany. • Founded by John Fagan (Maharishi University) in 1996.

  20. Transgenic landrace maizeSeries of events • Quist and Chapela publish Nature paper • Much criticism by science community • Nature editor says paper should never have been published • Ortiz-Garcia et al PNAS paper—no transgenic DNA is found • Piñeyro-Nelson, et al. Molecular Ecology paper claims transgenes come and go • Genetic ID claims authors misinterpret data • Probably low level of transgene presence? • Decision is made to allow field trials in Mexico of transgenic corn 2001-2002 2005 2009-2010

  21. The Rural Advancement Foundation International (now the ETC Group) renamed TPS or GURTs to TERMINATOR TECHNOLOGY and TRAITOR TECHNOLOGY Words are powerful!

  22. The case of “Terminator” technologyAKA Technology Protection SystemAKA Gene Use Restriction Technology http://cls.casa.colostate.edu/TransgenicCrops/terminator.html

  23. Control of plant gene expression Abstract A method for making a genetically modified plant comprising regenerating a whole plant from a plant cell that has been transfected with DNA sequences comprising a first gene whose expression results in an altered plant phenotype linked to a transiently active promoter, the gene and promoter being separated by a blocking sequence flanked on either side by specific excision sequences, a second gene that encodes a recombinase specific for the specific excision sequences linked to a repressible promoter, and a third gene that encodes the repressor specific for the repressible promoter. Also a method for making a genetically modified hybrid plant by hybridizing a first plant regenerated from a plant cell that has been transfected with DNA sequences comprising a first gene whose expression results in an altered plant phenotype linked to a transiently active promoter, the gene and promoter being separated by a blocking sequence flanked on either side by specific excision sequences to a second plant regenerated from a second plant cell that has been transfected with DNA sequences comprising a second gene that encodes a recombinase specific for the specific excision sequences linked to a promoter that is active during seed germination, and growing a hybrid plant from the hybrid seed. Plant cells, plant tissues, plant seed and whole plants containing the above DNA sequences are also claimed. US Patent 5,723,765; Inventors: Melvin Oliver, et al. issuedMarch 3, 1998—licensed to Delta and Pineland Control of plant gene expression A method for making a genetically modified plant comprising regenerating a whole plant from a plant cell that has been transfected with DNA sequences comprising a first gene whose expression results in an altered plant phenotype linked to a transiently active promoter, the gene and promoter being separated by a blocking sequence flanked on either side by specific excision sequences, a second gene that encodes a recombinase specific for the specific excision sequences linked to a repressible promoter, and a third gene that encodes the repressor specific for the repressible promoter. Also a method for making a genetically modified hybrid plant by hybridizing a first plant regenerated from a plant cell that has been transfected with DNA sequences comprising a first gene whose expression results in an altered plant phenotype linked to a transiently active promoter, the gene and promoter being separated by a blocking sequence flanked on either side by specific excision sequences to a second plant regenerated from a second plant cell that has been transfected with DNA sequences comprising a second gene that encodes a recombinase specific for the specific excision sequences linked to a promoter that is active during seed germination, and growing a hybrid plant from the hybrid seed. Plant cells, plant tissues, plant seed and whole plants containing the above DNA sequences are also claimed.

  24. Evolution of GMO controversies • Until 1998: few controversies • 1998-2001: “Golden age” of controversies—characterized by NGO and media frenzies. Scientists were passive. • 2002 until now: Fewer controversies. Why? • Over 1 billion acres and 100 trillion transgenic plants—no one has died. • Wary media • Proactive scientists (see response to Quist and Chapella).

  25. Historical global area and value of transgenic crops Marshall, A. 2012. Nature Biotechnology 30:207

  26. Global area of transgenic crops by country Marshall, A. 2012. Nature Biotechnology 30:207

  27. Big environmental benefitsof today’s transgenic cropsHerbicide tolerant crops have increased and encouraged no-till agriculture– less soil erosion.Over 1 million gallons of unsprayed insecticide per year.

  28. Risks • Weighed against benefits • Weighed against risks of competing practices and technologies (none are risk-free) • Weighed against not adopting Controversies result from oversimplifications coupled with a desire to inflame.

  29. “Ordinary Tomatoes Do Not Contain Genes, while Genetically Modified Ones Do” 1996 - 1998 People in different countries have varied knowledge about the facts of genetics and biotechnology Slide courtesy of Tom Hoban

  30. American Consumers’ Trust in Biotechnology Information Sources Slide courtesy of Tom Hoban

  31. Source of Information Trusted Most to Tell the Truth about Biotechnology(Includes ALL European Countries) Slide courtesy of Tom Hoban

  32. “I eat organic food and drink only green tea– gallons of it when I’m writing. I smoke cigarettes, but organic ones”* Discussing her “healthy” lifestyle in Organic Style magazine March 2005.

  33. Recipe for controversy(“food for naught”) • A dab of science (not too much and preferably not published) • A generous dollop of media and NGO interest • Lukewarm scientists (too busy with their own thing) • Science ignoring emotional or societal aspects • A ravenous public with a thirst for collusion • A sprinkling of celebrity

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