Do genetically modified crops affect animal reproduction? A review of the ongoing debate

In the past few years, genetically modified (GM) crops aimed at producing food/feed that became part of the regular agriculture in many areas of the world. However, we are uncertain whether GM food and feed can exert potential adverse effects on humans or animals. Of importance, the reproductive toxicology of GM crops has been studied using a number of methods, and by feeding GM crops to a number species of animals to ensure the safety assessment of GM food and feed. It appears that there are no adverse effects of GM crops on many species of animals in acute and short-term feeding studies, but serious debates of effects of long-term and multigenerational feeding studies remain. The aims of this review are to focus on the latest (last 3 to 4 years) findings and debates on reproduction of male and female animals after feeding daily diets containing the GM crops, and to present the possible mechanism(s) to explain their influences.     

转Bt基因抗虫作物对非靶标害虫的影响

转基因作物的长期大面积种植, 在为农业生产带来惠益的同时, 对农业生态系统的健康和稳定可能会产生潜在的影响。转基因作物表达的Bt蛋白对靶标害虫起到较好的控制效果, 而对Bt蛋白不敏感的非靶标害虫种群可能会迅速发展起来, 对作物造成为害。随着抗虫转基因作物的连续多年种植, 科学家们对于田间杀虫剂施用量的增减看法不尽一致。通过总结已有的研究报道, 本文以Bt玉米和Bt棉花为例, 分析了大田中非靶标害虫暴发的现状, 以及暴发的主要原因(如杀虫剂的使用、害虫天敌减少和物种替代)。在生产实践中, 抗虫作物的长期大面积释放导致广谱杀虫剂施用量减少, 田间非靶标害虫数量上升。因此今后需要继续开展更多的研究来综合评估种植转Bt基因作物产生的长期潜在影响, 优化害虫防治措施, 避免非靶标害虫暴发。     

Environmental change challenges decision-making during post-market environmental monitoring of transgenic crops

The ability to decide what kind of environmental changes observed during post-market environmental monitoring of genetically modified (GM) crops represent environmental harm is an essential part of most legal frameworks regulating the commercial release of GM crops into the environment. Among others, such decisions are necessary to initiate remedial measures or to sustain claims of redress linked to environmental liability. Given that consensus on criteria to evaluate ‘environmental harm’ has not yet been found, there are a number of challenges for risk managers when interpreting GM crop monitoring data for environmental decision-making. In the present paper, we argue that the challenges in decision-making have four main causes. The first three causes relate to scientific data collection and analysis, which have methodological limits. The forth cause concerns scientific data evaluation, which is controversial among the different stakeholders involved in the debate on potential impacts of GM crops on the environment. This results in controversy how the effects of GM crops should be valued and what constitutes environmental harm. This controversy may influence decision-making about triggering corrective actions by regulators. We analyse all four challenges and propose potential strategies for addressing them. We conclude that environmental monitoring has its limits in reducing uncertainties remaining from the environmental risk assessment prior to market approval. We argue that remaining uncertainties related to adverse environmental effects of GM crops would probably be assessed in a more efficient and rigorous way during pre-market risk assessment. Risk managers should acknowledge the limits of environmental monitoring programmes as a tool for decision-making.     

The impact of genetically modified crops on soil microbial communities.

Genetically modified (GM) plants represent a potential benefit for environmentally friendly agriculture and human health. Though, poor knowledge is available on potential hazards posed by unintended modifications occurring during genetic manipulation. The increasing amount of reports on ecological risks and benefits of GM plants stresses the need for experimental works aimed at evaluating the impact of GM crops on natural and agro-ecosystems. Major environmental risks associated with GM crops include their potential impact on non-target soil microorganisms playing a fundamental role in crop residues degradation and in biogeochemical cycles. Recent works assessed the effects of GM crops on soil microbial communities on the basis of case-by-case studies, using multimodal experimental approaches involving different target and non-target organisms. Experimental evidences discussed in this review confirm that a precautionary approach should be adopted, by taking into account the risks associated with the unpredictability of transformation events, of their pleiotropic effects and of the fate of transgenes in natural and agro-ecosystems, weighing benefits against costs.     

Probability functions to build composite indicators: A methodology to measure environmental impacts of genetically modified crops

There is an on-going debate on the environmental effects of genetically modified crops to which this paper aims to contribute. First, data on environmental impacts of genetically modified (GM) and conventional crops are collected from peer-reviewed journals, and secondly an analysis is conducted in order to examine which crop type is less harmful for the environment. Published data on environmental impacts are measured using an array of indicators, and their analysis requires their normalisation and aggregation. Taking advantage of composite indicators literature, this paper builds composite indicators to measure the impact of GM and conventional crops in three dimensions: (1) non-target key species richness, (2) pesticide use, and (3) aggregated environmental impact. The comparison between the three composite indicators for both crop types allows us to establish not only a ranking to elucidate which crop is more convenient for the environment but the probability that one crop type outperforms the other from an environmental perspective. Results show that GM crops tend to cause lower environmental impacts than conventional crops for the analysed indicators.     

Assuring the safety of genetically modified (GM) foods: the importance of an holistic,integrative approach

Genes change continuously by natural mutation and recombination enabling man to select and breed crops having the most desirable traits such as yield or flavour. Genetic modification (GM) is a recent development which allows specific genes to be identified, isolated, copied and inserted into other plants with a high level of specificity. The food safety considerations for GM crops are basically the same as those arising from conventionally bred crops, very few of which have been subject to any testing yet are generally regarded as being safe to eat. In contrast a rigorous safety testing paradigm has been developed for GM crops, which utilises a systematic, stepwise and holistic approach. The resultant science based process, focuses on a classical evaluation of the toxic potential of the introduced novel trait and the wholesomeness of the transformed crop. In addition, detailed consideration is given to the history and safe use of the parent crop as well as that of the gene donor. The overall safety evaluation is conducted under the concept known as substantial equivalence which is enshrined in all international crop biotechnology guidelines. This provides the framework for a comparative approach to identify the similarities and differences between the GM product and its comparator which has a known history of safe use. By building a detailed profile on each step in the transformation process, from parent to new crop, and by thoroughly evaluating the significance from a safety perspective, of any differences that may be detected, a very comprehensive matrix of information is constructed which enables the conclusion as to whether the GM crop, derived food or feed is as safe as its traditional counterpart. Using this approach in the evaluation of more than 50 GM crops which have been approved worldwide, the conclusion has been that foods and feeds derived from genetically modified crops are as safe and nutritious as those derived from traditional crops. The lack of any adverse effects resulting from the production and consumption of GM crops grown on more than 300 million cumulative acres over the last 5 years supports these safety conclusions.     

Comparing the refuge strategy for managing the evolution of insect resistance under different reproductive strategies

Genetically modified (GM) crops are used extensively worldwide to control diploid agricultural insect pests that reproduce sexually. However, future GM crops will likely soon target haplodiploid and parthenogenetic insects. As rapid pest adaptation could compromise these novel crops, strategies to manage resistance in haplodiploid and parthenogenetic pests are urgently needed. Here, we developed models to characterize factors that could delay or prevent the evolution of resistance to GM crops in diploid, haplodiploid, and parthenogenetic insect pests. The standard strategy for managing resistance in diploid pests relies on refuges of non-GM host plants and GM crops that produce high toxin concentrations. Although the tenets of the standard refuge strategy apply to all pests, this strategy does not greatly delay the evolution of resistance in haplodiploid or parthenogenetic pests. Two additional factors are needed to effectively delay or prevent the evolution of resistance in such pests, large recessive or smaller non-recessive fitness costs must reduce the fitness of resistance individuals in refuges (and ideally also on GM crops), and resistant individuals must have lower fitness on GM compared to non-GM crops (incomplete resistance). Recent research indicates that the magnitude and dominance of fitness costs could be increased by using specific host–plants, natural enemies, or pathogens. Furthermore, incomplete resistance could be enhanced by engineering desirable traits into novel GM crops. Thus, the sustainability of GM crops that target haplodiploid or parthenogenetic pests will require careful consideration of the effects of reproductive mode, fitness costs, and incomplete resistance.     

Potential for the environmental impact of transgenic crops

In recent years, there has been increasing interest in how changes in agricultural practice associated with the introduction of particular genetically modified (GM) crops might indirectly impact the environment. There is also interest in any effects that might be associated with recombinant and novel combinations of DNA passing into the environment, and the possibility that they may be taken up by microorganisms or other live biological material. From the current state of knowledge, the impact of free DNA of transgenic origin is likely to be negligible compared with the large amount of total free DNA. We can find no compelling scientific arguments to demonstrate that GM crops are innately different from non-GM crops. The kinds of potential impacts of GM crops fall into classes familiar from the cultivation of non-GM crops (e.g., invasiveness, weediness, toxicity, or biodiversity). It is likely, however, that the novelty of some of the products of GM crop improvement will present new challenges and perhaps opportunities to manage particular crops in creative ways.     

Impact of insect-resistant GM rice on pesticide use and farmers' health in China

The economic benefits of insect-resistant genetically modified(GM) crops have been well documented, but the impact of such crops and the consequent reduction in pesticide use on farmers' health remains largely unknown. Through the analysis of the data collected from the physical examination from farmers in China, we show that GM rice significantly reduces pesticide use and the resultant not only visible but also invisible adverse effects on farmers' neurological, hematological, and electrolyte system. Hence, the commercialization of GM rice is expected to improve the health of farmers in developing countries, where pesticide application is necessary to mitigate crop loss.     

GM crops: science, politics and communication

As the public debate in Europe about genetically modified (GM) crops heats up and the trade row between the United States and the European Union over GM food escalates, what better time to examine the issues with an international group of experts (Box 1). Their views are diverse, but they all agree that we need more impartial communication, less propaganda and an effective regulatory regime that is based on a careful case-by-case consideration of GM technology. It seems that GM crops are here to stay, so let us hope that these requirements are met and that the developing nations that perhaps have the most to gain from this technology can start to reap its benefits.     

The policy chicken and the science egg. Has applied ecology failed the transgenic crops debate?

Ecology has a long history of research relevant to and impacting on real-world issues. Nonetheless problems of communication remain between policy-makers and scientists because they tend to work at different levels of generality (policy deals with broad issues, science prefers specific questions), and complexity (policy-makers want simple answers, ecologists tend to offer multi-factorial solutions) and to different timescales (policy-makers want answers tomorrow, ecologists always seem to want more time). These differences are not unique to the debate about the cultivation of transgenic crops. Research on gene flow is used to illustrate how science and policy are intimately bound together in a value-laden, iterative and messy process unlike that characterised by the ‘encounter problem—do science—make policy’ model. It also demonstrates how the gap between science and policy is often characterised by value-laden language. Scientists involved in ERA for transgenic crops may find their engagement with policy- and decision-makers clouded by misunderstanding about what one should expect from the other. Not the least of these, that science can define harm, is explored in a discussion of the UK Farm Scale Evaluations of herbicide-tolerant GM crops. The varied responses to these extensive trials highlight the problems of linking specific scientific experiments with broad policy objectives. The problems of applied ecology in the transgenic crops debate are not unique but may differ from other areas of environmental policy in the intense politicisation of the debate, the emphasis on assessment of risk and the particularly broad policy objectives.     

Moving beyond the GM Debate

Once again, there are calls to reopen the debate on genetically modified (GM) crops. I find these calls frustrating and unnecessarily decisive. In my opinion the GM debate, on both sides, continues to hamper the urgent need to address the diverse and pressing challenges of global food security and environmental sustainability. The destructive power of the debate comes from its conflation of unrelated issues, coupled with deeply rooted misconceptions of the nature of agriculture.

This article is part of the PLOS Biology Collection “The Promise of Plant Translational Research.”

For many people, genetic modification (GM) has become the poster child for everything they consider bad about modern agriculture. It represents the domination of the food supply chain by profit-driven multinational companies. It represents the systematic replacement of important ecosystems with huge high-intensity farms growing monocultures of commodity crops. It represents humankind''s evil manipulation of Nature for personal gain and greed, at the expense of the planet and of future generations. These are important concerns. It is reasonable to be disturbed by some of the current trends in agricultural practices, with fears fuelled by past errors, such as the previous emergence in the UK of bovine spongiform encephalopathy (BSE). However, none of these issues has anything to do with GM as a technique for improving or introducing plant traits. A complete ban on the use of GM in crop development would have no impact on any of them. For as long as we imagine that GM itself is the cause of these problems, they are free to escalate unchecked.A defining question of the 21^st century is: How can we achieve a reliable, sustainable, equitable supply of nutritious food for a growing and increasingly urbanized world population in the face of climate change? This is a complex question with agricultural productivity constituting only a small part of it, and in turn, GM only a small part of that. It is essential that we move forward to address this question without being continuously sidetracked by the GM debate. How can this be achieved?First, it is necessary to move on from the well-worn logical fallacy that anything natural is good, and anything unnatural is bad. The application of this fallacy to agriculture is an excellent illustration of why it is so flawed. Plants evolved by natural selection, driven by the survival of the fittest. As a result, naturally, they are defended to the hilt from herbivores of all kinds, including humans. We know this. No one sends their children into the woods saying “Eat anything you find. It''s all natural, so it must be good for you.” The seeds of plants are particularly well protected, because they are, of course, the plant''s children, their ticket to posterity. Seed is therefore usually tough, indigestible, minimally resourced, and often laced with toxins. Yet plant seeds are now our major source of calories. The cereal crops we eat bear little resemblance to their naturally selected ancestors, and the environments in which we grow them are equally highly manipulated and engineered by us. We have, over the last 10,000 years, bred out of our main food plants all kinds of survival strategies that natural selection put in. This has drastically reduced their competitiveness in nature, but equally dramatically increased their utility in feeding us. Agriculture is the invention of humans. It is the deliberate manipulation of plants (and animals) and the environment in which they grow to provide food for us. The imperative is not that we should stop interfering with nature, but that we should interfere in the best way possible to provide a reliable, sustainable, equitable supply of nutritious food. To do this we need to understand how nature works. That''s what science is all about.This is easy to say, but concepts of the inherent goodness of Nature, and the inherent dangers of human interventions through science, are deeply ingrained in the way many people think, particularly in the context of food. This is an understandable response to concerns over the industrialization and unsustainable intensification of agriculture described above. You only have to walk down the aisles of a supermarket to see that “all natural” and “nothing artificial” sells things. These words sell products because they are so strongly culturally associated with environmental sustainability and well-being, exploiting people''s interest in protecting the environment and their health. However, many of the products people think of as natural, such as cereal crops, are profoundly unnatural and wouldn''t exist without human intervention; and many things people think of as artificial, such as “chemicals,” can be made with no human involvement at all. Similarly, many “natural” things are extremely bad news, such as aflatoxins, and many “artificial” things are widely accepted to be an extremely good idea, such as cereal crops (again). The only way to determine whether something is environmentally sustainable or healthy is to do the science and find out. Guessing based on cultural norms, amplified by aggressive marketing strategies is understandable, but will not deliver the desired outcome: a sustainable supply of healthy food. People need to be empowered to make decisions in a different way. For example, in the UK there is now a well-established health wheel traffic light system on foods in supermarkets, indicating through a simple graphic the sugar, fat, salt, and calorific content of the product. Perhaps there could be a similar sustainability wheel, building on such initiatives as Leaf (for Linking Environment and Farming – a UK organization that promotes sustainable food and farming and that identifies food produced to high environmental standards to consumers with a Leaf logo) [1]. This could be combined with the stricter application of advertising standards, preventing the fostering of misleading claims about what counts as “natural” and of misleading implications about the associated health and environmental benefits.Second, we need to get past the idea that GM, as a technique for crop genetic improvement, is specifically and generically different from other approaches, including conventional selective breeding. GM involves introducing a gene directly into the genome of an organism. The introduced gene can be one found in other members of that species or it could be from a different species. The most distinctive generic thing about a GM crop, in comparison to one produced by conventional selective breeding, would therefore appear to be the insertion of a piece of DNA into its genome, a process that is certainly not unique to GM crops. Even the movement of genes between species is not GM-specific, and indeed GM crops need not be modified with genes from a different species. Many viruses can insert their genomes into that of their host as a normal part of their life cycle. These viral sequences, and many related genetic elements, such as retroposons, accumulate over evolutionary time and can continue to move about the genomes of their hosts, creating new DNA insertion sites. Thus, every conventionally bred rice crispy or cornflake you had for breakfast probably differs from every other one by the insertion of a piece of DNA at an unknown site in its genome.There is really nothing generic to be said about GM as a plant breeding technique. Almost all the media reports purporting to be about the effects of GM are in fact about effects of the specific trait that has been introduced into the GM crop. Currently, there are only two widely deployed GM traits: herbicide tolerance and insect resistance. Concerns purporting to be about GM are almost all about one or other of these traits. For example, a large, farm-scale evaluation of the environmental impacts of three herbicide-tolerant GM crops conducted in the UK between 1999 and 2006 [2] was widely reported as demonstrating that GM is bad for wildlife. What in fact it showed was that effective weed control is bad for wildlife. Weeds are required to support biodiversity in agricultural environments, and are currently under threat from winter planting regimes, non-GM herbicide-tolerant crops, and a range of increasingly sophisticated weed control strategies. Banning GM crops will not address this problem. It is wrong to imply that growing GM crops, rather than effective weed control, is the cause of negative effects on biodiversity. It is not because a crop is GM that weeds are reduced; many GM crops have no impact on weeds at all. It is because a crop, GM or otherwise, is herbicide tolerant and sprayed with weed killers that reduce weed populations. The claim that biodiversity is reduced because a GM crop was grown detracts attention from the real issue, namely how to balance the positive effects of weeds in supporting biodiversity with their negative impacts on agricultural productivity.This confusion between the effects of a new trait and the method by which it has been introduced is enshrined in the way new crops are licensed for commercial release in many countries. In the European Union (EU), a new herbicide-tolerant GM crop, produced by introducing a single gene conferring herbicide tolerance, must go through a lengthy procedure of testing aimed at assessing its potential health and environmental impacts [3]. Such an assessment would include concerns about impacts on wildlife, as described above, and about the generation of so-called super weeds by out-crossing of the GM crop to wild relatives or caused by the over-use of herbicides. Meanwhile, a herbicide-tolerant crop produced by mutation of a single endogenous gene has no such testing, and the breeders need only to demonstrate that it is stable and significantly different from already registered crops. All the environmental concerns associated with GM herbicide tolerance are equally applicable to non-GM herbicide tolerance. There are also considerable agronomic and environmental benefits that could accrue from herbicide tolerant crops, such as reduced soil erosion through reduced need for ploughing [4]. These need to be weighed against the risks and an appropriate decision reached. This decision is about weed control, not about GM. In my opinion, there is therefore no justification for considering GM vs non-GM herbicide tolerant crops differently. Their assessment, from a regulatory viewpoint and in terms of their environmental impact, should be based on the distinctive trait they carry.The GM-specific regulatory system currently in place creates huge financial barriers for GM crop introduction, which ironically is one of the main reasons why almost the only applications in the field today are driven by big business. These days, the cost of developing a GM crop is relatively affordable. Meanwhile, non-GM crops, sometimes with new traits, are released with relatively little scrutiny of their impacts on the environment or on food safety. This is increasingly an issue as we continue to develop new and ever more sophisticated ways to introduce desirable traits into crops, for example by genomic assisted breeding or by genome editing [5]. These new tools provide exciting and much needed opportunities for crop genetic improvement, but in my view they also demand a more sensible licensing system that assesses all new crops based on the traits they carry rather than on the method by which they were introduced [5],[6].The current system does little to protect the environment or the food chain and is ill-equipped to cope with the new approaches to plant breeding now coming on line. A trait-based system, bringing a proportional level of scrutiny to all crops that carry a new trait, could provide the checks and balances that should go hand in hand with innovation. We definitely need crop genetic improvement [4], using whatever method is best, and it is precisely because we do that we also need an evidence-based and proportional system for assessing new crops for environmental and health impacts.A related issue, which will be similarly challenged by new genetic improvement techniques, is that of patent protection for crops. While conventionally bred crops can be protected by various means, such “variety” protection systems include exemptions for farmers that permit them to save seed for next year''s planting and for breeders to include the variety in breeding programmes. In contrast, GM crops can be protected by so-called utility patents, which can protect the use of a specific gene to confer a trait. These patents are much more restrictive and prohibit both seed saving by farmers and exemptions for plant breeders. The harmonisation of the crop variety licensing system to focus on novel traits, however introduced, could reasonably be widened to include an examination of the patent protection system for such traits. If the licensing system were to become less expensive, the argument for restrictive utility patents on such traits is reduced.We now have a wealth of opportunities for crop genetic improvement, with an impressive arsenal of tools and techniques available. To deploy these effectively, we need to move well beyond the GM debate to a much wider debate about food production. What methods of farming provide reliable and high yields in a sustainable way? What is the role of multinational companies in delivering food security? What political and societal changes are needed to drive more equitable food distribution? How can waste be reduced? These are big complex questions with big complex answers and no simple dogmatic solution. No single farming method or crop improvement technique is a panacea, nor is it the cause of the problem. Such complex problems with correspondingly complex and multifaceted solutions are difficult. They don''t make rousing campaign slogans or eye-catching tabloid headlines, but we have got to find a way to address them, in all their complexity.The most frustrating thing about this situation is that almost everyone wants the same outcome: a reliable, sustainable, equitable supply of nutritious food. For issues this big, there will of course be differences of opinion about how to move forward, what to prioritise, and how to decide. These are important areas for debate. GM, as a technique, is not.     

Environmental fate and behaviour of antibiotic resistance genes and small interference RNAs released from genetically modified crops

Rising global populations have amplified food scarcity across the world and ushered in the development of genetically modified (GM) crops to overcome these challenges. Cultivation of major crops such as corn and soy has favoured GM crops over conventional varieties to meet crop production and resilience needs. Modern GM crops containing small interference RNA molecules and antibiotic resistance genes have become increasingly common in the United States. However, the use of these crops remains controversial due to the uncertainty regarding the unintended release of its genetic material into the environment and possible downstream effects on human and environmental health. DNA or RNA transgenes may be exuded from crop tissues during cultivation or released during plant decomposition and adsorbed by soil. This can contribute to the persistence and bioavailability in soil or water environment and possible uptake by soil microbial communities and further passing of this information to neighbouring bacteria, disrupting microbial ecosystem services such as nutrient cycling and soil fertility. In this review, transgene mechanisms of action, uses in crops, and knowledge regarding their environmental fate and impact to microbes are evaluated. This aims to encapsulate the current knowledge and promote further research regarding unintended effects transgenes may cause.     

Commercializing genetically modified crops under EU regulations: objectives and barriers

Agriculture faces serious problems in feeding 9 billion people by 2050: production must be increased and ecosystem services maintained under conditions for growing crops that are predicted to worsen in many parts of the world. A proposed solution is sustainable intensification of agriculture, whereby yields are increased on land that is currently cultivated, so sparing land to deliver other ecosystem services. Genetically modified (GM) crops are already contributing to sustainable intensification through higher yields and lower environmental impacts, and have potential to deliver further significant improvements. Despite their widespread successful use elsewhere, the European Union (EU) has been slow to introduce GM crops: decisions on applications to import GM commodities are lengthy, and decision-making on applications to cultivate GM crops has virtually ceased. Delayed import approvals result in economic losses, particularly in the EU itself as a result of higher commodity prices. Failure to grant cultivation approvals costs EU farmers opportunities to reduce inputs, and results in loss of agricultural research and development from the EU to countries such as the United States and China. Delayed decision-making in the EU ostensibly results from scientific uncertainty about the effects of using GM crops; however, scientific uncertainty may be a means to justify a political decision to restrict cultivation of GM crops in the EU. The problems associated with delayed decision-making will not improve until there is clarity about the EU's agricultural policy objectives, and whether the use of GM crops will be permitted to contribute to achieving those objectives.     

Genetically modified crops and small-scale farmers: main opportunities and challenges

Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countries. The most significant advantages of GM crops include being independent to farm size, environment protection, improvement of occupational health issues, and the potential of bio-fortified crops to reduce malnutrition. Challenges faced by small-scale farmers for adoption of GM crops comprise availability and accessibility of GM crop seeds, seed dissemination and price, and the lack of adequate information. In addition, R&D and production costs in using GM crops make it difficult for these farmers to adopt the use of these crops. Moreover, intellectual property right regulations may deprive resource poor farmers from the advantages of GM technology. Finally, concerns on socio-economic and environment safety issues are also addressed in this paper.     

The release of genetically modified crops into the environment. Part II. Overview of ecological risk assessment

Despite numerous future promises, there is a multitude of concerns about the impact of GM crops on the environment. Key issues in the environmental assessment of GM crops are putative invasiveness, vertical or horizontal gene flow, other ecological impacts, effects on biodiversity and the impact of presence of GM material in other products. These are all highly interdisciplinary and complex issues. A crucial component for a proper assessment is defining the appropriate baseline for comparison and decision. For GM crops, the best and most appropriately defined reference point is the impact of plants developed by traditional breeding. The latter is an integral and accepted part of agriculture. In many instances, the putative impacts identified for GM crops are very similar to the impacts of new cultivars derived from traditional breeding. When assessing GM crops relative to existing cultivars, the increased knowledge base underpinning the development of GM crops will provide greater confidence in the assurances plant science can give on the risks of releasing such crops.     

Environmental risk assessment of transgenic miraculin-accumulating tomato in a confined field trial in Japan

The commercial use of genetically modified (GM) crops requires prior assessment of the risks to the environment when these crops are grown in the field or distributed. Assessments protocols vary across countries and GM crop events, but there is a common need to assess environmental biosafety. In this study, we conducted an environmental risk assessment in a confined field of GM tomato plants that can produce miraculin, a taste-altering protein that causes sour tastes to be perceived as sweet, for practical use in Japan. The evaluation was conducted for 1) competitiveness (the ability to compete with wild plants for nutrients, sunlight, and growing areas and prevent their growth) and 2) the production of toxic substances (the ability to produce substances that interfere with the habitat and growth of wild plants, animals, and microorganisms). Investigations of plant morphology and growth characteristics as well as tolerance to low temperature during early growth and overwintering for assessment endpoints related to competitiveness showed no biologically meaningful difference between GM tomato and non-GM tomato. In addition, harmful substances in plant residues and root secretions were assessed by the plow-in method, succeeding crop test and soil microflora tests, and it was determined that GM tomato does not exhibit an increase in harmful substances. Based on these results, it was concluded that GM miraculin-accumulating tomato is comparable to conventional tomato and is unlikely to have unintended adverse effects in the natural environment of Japan.     

The release of genetically modified crops into the environment. Part I. Overview of current status and regulations

In the past 6 years, the global area of commercially grown, genetically modified (GM) crops has increased more than 30-fold to over 52 million hectares. The number of countries involved has more than doubled. Especially in developing countries, the GM crop area is anticipated to increase rapidly in the coming years. Despite this high adoption rate and future promises, there is a multitude of concerns about the impact of GM crops on the environment. Regulatory approaches in Europe and North America are essentially different. In the EU, it is based on the process of making GM crops; in the US, on the characteristics of the GM product. Many other countries are in the process of establishing regulation based on either system or a mixture. Despite these differences, the information required for risk assessment tends to be similar. Each risk assessment considers the possibility, probability and consequence of harm on a case-by-case basis. For GM crops, the impact of non-use should be added to this evaluation. It is important that the regulation of risk should not turn into the risk of regulation. The best and most appropriate baseline for comparison when performing risk assessment on GM crops is the impact of plants developed by traditional breeding. The latter is an integral and accepted part of agriculture.     

Transgenic,transplastomic and other genetically modified plants: a Canadian perspective

Since the mid 1990s, genetically modified (GM) crops have been grown commercially in Canada on a scale that has increased steadily over the years. An intense debate ensued, as elsewhere, and many fears were expressed regarding not only the technology itself but some of the main GM crops being grown. It would seem appropriate at this time to examine how these novel crops compare to crops bred by more traditional means and what impacts these GM crops have had based on experience and not merely on conjecture. To begin, we will put things in a historical perspective and recall how domestication and conventional plant breeding have shaped the crops of today. Then, we will describe briefly the distinctive features of GM plants (obtained so far mainly by nuclear transgenesis) and how these novel crops are regulated in Canada. We will then give two examples of widely grown GM crops in Canada (insect-resistant corn and herbicide-tolerant canola) and examine the main questions that were raised as well as the actual impacts these crops have had on the farm. These examples will help us outline some of the limitations of the current generation of GM plants and, finally, we will try to get a glimpse of the future by examining some recent technical developments in the field of recombinant DNA technologies applied to plant breeding.