Transgenic Animals And Prion Diseases
Prions are self-replicating proteins, a form of which is responsible for mad cow disease and associated CJD (the human form). There is concern among some scientists that the engineering of transgenic animals may create conditions that foster the development of new prion borne diseases. Prion diseases are sometimes called spongiform encephalopathies due to the appearance of the brain tissue following post mortem examinations. Prion diseases in animals include scrapie (sheep), TME or transmissible mink encephalopathy (mink), CWD or chronic wasting disease (muledeer, elk), BSE or bovine spongiform encephalopathy (cows). In humans prions cause CJD (Creutzfeld-Jacob Disease), GSS (Gerstmann-Straussler-Scheinker syndrome), FFI (Fatal familial Insomnia), Kuru, and Alpers Syndrome.
Wills, P.R. (1996) Transgenic animals and prion diseases: hypotheses, risks, regulations and policies. New Zealand Veterinary Journal 44, 33-36.
(Responding to the paper below)
O'Neil, B.D. (1995) Transgenic animals and prion diseases. New Zealand Veterinary Journal 43, 88.
Wills, P.R. (1995) Transgenic animals and prion diseases. New Zealand Veterinary Journal 43, 86-87.
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General Warnings/Admonitions
A number of studies mention general warnings about the safety of genetic modification, in terms of food safety and in particular potential allergenic effects. Genetic modification is often about introducing gene sequences into organisms that enable them to produce proteins that they were not otherwise able to produce. Proteins are fundamental building blocks in living organisms and play a wide variety of physiological roles. Sometimes novel proteins comprise a desired (i.e. target) effect in a food crop, where that crop (or any crop) has never expressed that protein (e.g. it may be from an animal). Such novel proteins may also have never been in the human diet and as such are novel not only to the plant but novel to those that consume such plants. Allergens are commonly proteins, and novel proteins are potential allergens. Some allergens are fatal (e.g. peanuts are fatal to some people) where they produce an anaphylactic reaction (as with bee stings). Given that novel proteins are potential allergens, and given that novel allergens are potentially fatal, it stands to reason that any product that was produced for human consumption (whether as a food or a drug) should be subject to safety testing that included testing for potential allergenicity. Such testing is required for pharmaceuticals but not for GM foods; hence the concern.
The papers listed below are not restricted to those concerned about potential allergenicity of GM foods, but also include other concerns as well, including the application of the precautionary principle to genetic modification, genetic pollution, and general health risks worth consideration according to these scientists.
Antoniou, M. (1996) Genetic pollution. Nutritional Therapy Today 6, 8-11.
Christie, B. (1999) Scientists call for moratorium on genetically modified foods. British Medical Journal 318, 483.
Domingo, J.L. (2000) Health risks of GM foods: many opinions but few data. Science 288, 1748-1749.
Domingo, J.L. and Arnáis, M.G. (2000) Riesgos sobre la salud de los alimentos modificados genéticamente: una revision bibliografica. Rev. Esp. Salud Pública 74, 255-261.
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Eubanks, M. (2002) Allergies à la carte: is there a problem with genetically modified foods? Environmental Health Perspectives 110, A130-131.
Helm, R.M. (2002) Biotechnology and food allergy. Current Allergy and Asthma Reports 2, 55-62.
Millstone, E.; Brunner, E. and Mayer, S. (1999) Beyond 'substantial equivalence' Nature 401, 525-526.
Myhr, A.I. and Traavik, T. (1999) The precautionary principle applied to deliberate release of genetically modified organisms (GMOs). Microbial Ecology in Health and Disease 11, 65-74.
Myhr, A.I. and Traavik, T. (2002) the precautionary principle: scientific uncertainty and omitted research in the context of GMO use and release. Journal of Agricultural and Environmental Ethics 15, 73-86.
Nielsen, K.M.; Bones, A.M.; Smalla, K. and van Elsas, J.D. (1998) Horizontal gene transfer from transgenic plants to terrestrial bacteria; a rare event? FEMS Microbiology Reviews 22, 79-103.
Ryder, M. (1994) Key issues in the deliberate release of genetically-manipulated bacteria. FEMS Microbiology Ecology 15, 139-146.
Schubert, D. (2002) A different perspective on GM food. Nature Biotechnology 20, 969.
Warner, J.O. (2002) Editorial: genetically modified food and the pediatric allergist. Pediatric Allergy and Immunology 13, 73-74.
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Wolfenbarger, L.L. and Phifer, P.R. (2000) The ecological risks and benefits of genetically engineered plants. Science 290, 2088-2093.
Conclusion
It should be clear from the above collection of scientific publications (which is not exhaustive by any means), that concern about the risks of genetic modification is not merely a debate between scientists on the one hand and well meaning but mis-informed lay people on the other. It is a genuine scientific and philosophical debate. Given that studies such as those listed above exist in the published literature, and are therefore available to regulators and decision-makers (and their advisory staff) world wide, there is no reason why they cannot be taken into account when regulatory decisions are made on the use and control of GM technologies and their applications.
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