Alan Gray

Will hybrids of genetically modified crops invade natural communities

A perceived danger of genetic modification of crops is that crop hybrids may not only become more-pernicious weeds of agriculture but that they may also become invasive of natural communities. New information on the extent of crop hybridization and the characteristics of modified crops is facilitating more-accurate assessments of these risks.

Crop genetics: Reducing transgene escape routes

One of the main concerns about genetically modified crops is the risk of contaminating ‘natural’ populations with the introduced genes. A technical development that reduces this risk is now reported, and the principle is simple — rather than introducing transgenes into the nuclear genome, from which they can be spread in the form of pollen, the genes are introduced into the chloroplast DNA. Chloroplasts are maternally inherited, so wild relatives of transgenic plants cannot be contaminated.

Genetic basis and detection of unintended effects in genetically modified crop plants

In January 2014, an international meeting sponsored by the International Life Sciences Institute/Health and Environmental Sciences Institute and the Canadian Food Inspection Agency titled “Genetic Basis of Unintended Effects in Modified Plants” was held in Ottawa, Canada, bringing together over 75 scientists from academia, government, and the agro-biotech industry. The objectives of the meeting were to explore current knowledge and identify areas requiring further study on unintended effects in plants and to discuss how this information can inform and improve genetically modified (GM) crop risk assessments. The meeting featured presentations on the molecular basis of plant genome variability in general, unintended changes at the molecular and phenotypic levels, and the development and use of hypothesis-driven evaluations of unintended effects in assessing conventional and GM crops. The development and role of emerging “omics” technologies in the assessment of unintended effects was also discussed. Several themes recurred in a number of talks; for example, a common observation was that no system for genetic modification, including conventional methods of plant breeding, is without unintended effects. Another common observation was that “unintended” does not necessarily mean “harmful”. This paper summarizes key points from the information presented at the meeting to provide readers with current viewpoints on these topics.

Environmental risk assessment of GE plants under low-exposure conditions

The requirement for environmental risk assessment (ERA) of genetically engineered (GE) plants prior to large scale or commercial introduction into the environment is well established in national laws and regulations, as well as in international agreements. Since the first introductions of GE plants in commercial agriculture in the 1990s, a nearly universal paradigm has emerged for conducting these assessments based on a few guiding principles. These include the concept of case-by-case assessment, the use of comparative assessments, and a focus of the ERA on characteristics of the plant, the introduced trait, and the receiving environment as well as the intended use. In practice, however, ERAs for GE plants have frequently focused on achieving highly detailed characterizations of potential hazards at the expense of consideration of the relevant levels of exposure. This emphasis on exhaustive hazard characterization can lead to great difficulties when applied to ERA for GE plants under low-exposure conditions. This paper presents some relevant considerations for conducting an ERA for a GE plant in a low-exposure scenario in the context of the generalized ERA paradigm, building on discussions and case studies presented during a session at ISBGMO 12.

Invasive Spartina: lessons and challenges

The grass genus Spartina provides one of the most exciting research topics in plant invasion and evolutionary ecology. It contains several species that have become highly successful invaders of intertidal mudflats and saltmarshes (Ainouche et al. 2009; Strong and Ayres 2013). The critical ecological role of several Spartina species as ‘‘ecosystem engineers’’ on coastal salt marshes, their remarkable history punctuated by natural or human-mediated introductions outside their native range, rapid expansion, and propensity to interspecific hybridization and polyploid speciation have long captured the attention of researchers and institutions involved in land management. One of the most spectacular cases is illustrated by the hexaploid S. alterniflora, native to the North American Atlantic coast, and its repeated introductions over the last two centuries, southward (e.g. Brazil, Argentina, Bortolus et al. 2015; South-Africa, Adams et al. this issue), westward to the Pacific coast of California (Strong and Ayres 2013), eastward to the west European Atlantic coasts (Ainouche et al. 2009), and to China, where populations have spectacularly expanded in the last decade (Li et al. 2009). In Europe, hybridization between S. alterniflora and the native S. maritima resulted in the formation of a vigorous and successful allododecaploid species, Spartina anglica (Hubbard 1968), which rapidly expanded on European saltmarshes and is now introduced in several continents. This system has become a classical model of recent polyploid speciation in a well-documented historical context, which provided invaluable insights into ecological, genetic, and genomic consequences of a new species expansion (Gray and Benham 1990; Gray et al. 1991; Ainouche et al. 2004, 2012).Whereas S. anglica has been a successful invader by occupying a formerly largely vacant vertical intertidal niche (Gray et al. 1991, 1995; Gray 1992), in California, hybridization of S. alterniflora with the native S. foliosa resulted in the formation of introgressant hybrids outcompeting the native genotypes (Ayres et al. 2004). The multiple ecological and evolutionary consequences of S. alterniflora invasion and expansion have generated contrasted attitudes and policies (e.g., highly valued on the North American Atlantic coast, or considerable efforts at eradication on the North American Pacific coast). The South American S. densiflora appears also as a successful invader following its introductions into northwest America (California) and to western Europe (Spain), where it Guest editors: Alan Gray and Malika Ainouche/Invasive Spartina.

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.