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Safety of Genetically Engineered Crops March 2001 VIB publication Flanders Interuniversity Institute for Biotechnology Editor: René Custers regulatory affairs manager, VIB This report can be obtained from: VIB Rijvisschestraat 120 B-9052 Zwijnaarde, Belgium tel.: ++32 (0)9 244 66 11 fax.: ++32 (0)9 244 66 10 e-mail: [email protected] web: http://www.vib.be Responsible publisher: Jo Bury, VIB Rijvisschestraat 120 9052 Zwijnaarde Nothing from this publication may be copied and/or made public for commercial purposes. For other purposes the source has to be mentioned. © March 2001 Contents A. Introduction . 4 1. Setting the scene . .4 2. What is the debate on genetically engineered crops all about? . .4 3. What does this report do and what does it not do? . .5 B. Some information on breeding, genetic engineering and agricultural practices . 6 1. Conventional breeding and selection . .6 2. Genetic engineering of plants . .7 3. Changes in plants obtained by genetic engineering or by conventional breeding . .8 4. Differences between conventional breeding and genetic engineering . .11 5. Environmental effects of current agricultural practices . .12 C. Summary . 13 D. Discussion . 20 E. Safety aspects of genetically engineered crops . .26 1. Toxicity and Food Safety of Genetically Engineered Crops . .27 Jan Pedersen, Folmer D. Eriksen, Ib Knudsen 2. Safety of Genetically Engineered Plants: an Ecological Risk Assessment of Vertical Gene Flow . .60 Klaus Ammann, Yolande Jacot, Pia Rufener Al Mazyad 3. Effects on Non-target Organisms of the Release of Genetically Modified Crops into the Environment . .88 Julian Kinderlerer 4. Allergenicity of Foods derived from Genetically Modified Organisms . .108 André Penninks, Leon Knippels, Geert Houben 5. The Biosafety of Antibiotic Resistance Markers in Plant Transformation and the Dissemination of Genes through Horizontal Gene Flow . .135 Philippe Gay Annex 1: Overview of referees . .160 A. Introduction 1. Setting the scene Genetically engineered crops have been and still are a subject of public controversy. Debate started in 1986 when the first field trials were initiated. The debate has taken a second and more profound round after the first ships with genetically engineered soybeans arrived in Europe in the autumn of 1996. In February 1997, the worldwide presentation of Dolly the cloned sheep has furthered the awareness of the impact of biotechnology among the general public. Especially in Europe the debate on genetically engineered crops is now very intense, but also in the US new rounds of discussion can be seen. 2. What is the debate on genetically engineered crops all about? The issues that are subject of the debate on genetically engineered crops can be divided into the following categories: 1. Biological questions Are genetically engineered crops dangerous for human health? What about food safety? Are there risks for our environment and the organisms living in our countryside? Do they pose a threat to biological diversity? How can they help attain sustainability? All these questions are repeatedly asked and perhaps they are not adequately answered or perhaps also new questions keep arising as the technology develops further and is applied to an ever increasing scale. 2. Societal questions What do genetically engineered crops mean for the power- and dependence relationships in the food chain? What about patents and ownership? How important is freedom of choice and how can it be guaranteed? What do genetically engineered crops mean for (our relationship with) the developing countries? What about the economics of genetically engineered crops? Underlying the two debates described above there are questions relating to the direction in which our society wants to develop. What are the goals our society strives for? What are the problems that we face today in our agriculture and environment and how can these problems be solved or circumvented? What developments or technologies can seriously contribute to the solving of these problems? And what criteria do we use to evaluate and weigh these different developments against each other? Often these goals and criteria are not made explicit, but implicitly they play an important role in the debate, because they determine the attitudes of different stakeholders in the debate. 4 Safety of Genetically Engineered Crops 3. What does this report do and what does it not do? This report wants to contribute to the discussion on some of the biological risks of genetically engineered crops, namely those that are subject of the different environmental and food regulations that apply to genetically modified food crops. In the debate about these crops the following issues come up very frequently: 1. Toxicity and food safety of genetically engineered crops 2. Vertical gene flow of genetically engineered crops 3. The effects of genetically engineered crops on non-target organisms 4. Allergenicity of foods derived from genetically engineered crops 5. The biosafety of antibiotic resistance markers in plant transformation and the dissemination of genes through horizontal gene flow This report contains for each of these topics a state-of-the-art review that has been written by a respected scientist with expertise in the issues involved (part E of this report). The reviews have been refereed by a number of peers, also experts in the subjects involved (see annex 1). These reviews are a summary of the current scientific knowledge on the safety aspects of genetically engineered crops, show what is known about the current genetically engineered crops that are on the market, and make some recommendations for future research and safety evaluations. The reviews do not represent an opinion of VIB as an institute, but should be seen as useful material gathered by VIB for further discussions. VIB has the ambition to disseminate this information very broadly, so it can be used by as many persons and organizations as possible that want to participate in the debate. This report does not touch upon all aspects of the discussion on the biological risks of genetically engineered crops, nor does it touch upon the issues catalogued above as ‘societal questions’ or ‘goals society strives for’. VIB acknowledges the importance of these issues, but has chosen in this instance to limit the scope of the report to the risk assessment aspect. Introduction 5 B. Some Information on Breeding, Genetic Engineering and Agricultural Practices 1. Conventional breeding and selection The crops that are used in our current agriculture have been derived from wild plants during a long process of domestication and selective breeding. Selective breeding is the improvement or alteration of crops by selecting only those individual plants that have certain desired properties. Selective breeding has been intensified dramatically during the 20th century and has become a highly specialized profession. Sexually compatible individual crop plants with different characteristics are crossed to generate offspring combining these characteristics, resulting in plants with possibly interesting phenotypes. Whether the desired characteristics are actually combined is a matter of chance. Many individual crosses have to be made to generate one new variety. During the last century the number of techniques for generating new varieties has been widely enlarged. Important techniques are: G Hybridization (to generate ‘hybrid vigour’1). G Alteration of Ploidy2 (haploids, tetraploids, etc.). G Induction of mutations through irradiation or the use of chemical mutagenic agents. Seeds are treated with chemical agents or irradiation resulting in mutations (alterations) in the genetic make up of the plant. Individual plants with different mutations in their genome are grown, and individual plants with interesting phenotypes are selected and screened. The mutations result in a greater genetic variation. G Somaclonal variation. In-vitro multiplication of plants is used to generate individuals with different phenotypes. These differences are thought to be the result of genome instability in the in-vitro stages which results in plants (clones) with different phenotypes from one and the same parent plant. G Embryo rescue Embryo rescue is the rescue of embryo’s of a cross between two plants that normally – in nature - would not result in offspring, thus enabling certain ‘wide crosses’ (crosses between plants that in nature are not sexually compatible). Such crosses have only been made with plants within one family. G Anther culture Anthers are grown in-vitro and hormones are used to regenerate plants from the anthers. G Marker assisted breeding. The use of molecular markers3 associated with certain phenotypic characteristics to add more precision to breeding and to speed the selection. 1Hybrid vigour is the result of the combination of two different inbred lines, where the result hybrid shows a far better performance than could be expected from the performance of two parent lines (1/2+1/2>1). 2The ploidy number shows how many times one chromosome is present in the genome of an individual. Haploids have only one of each chromosome (1N), diploids have two of each chromosome (2N), and tetraploids have four of each chromosome (4N). 3 A molecular marker is a genetic marker (a piece of DNA) that co-segregates with a particular trait. 6 Safety of Genetically Engineered Crops Many of our currently used food crops do not resemble their wild ancestors anymore (see for instance maize and its wild ancestor teosinte). Others are still more close to their wild relatives