ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIt is critical to base scientific risk assessment of genetically engineered organisms (GEOs) on appropriate scientific concepts. A variety of ‘generic safety’ models has now largely been recognized to have been based on outdated scientific thinking. One broad safety argument that is still used is that genetic engineering categorically is nothing but an extension of selective breeding. It is explained here, though, that the mechanisms and potentials of the two can be profoundly different. This does not mean that every GEO is ecologically dangerous; but some types of GEOs may be considerably more risky than what could be produced with selective breeding, especially when an ecologically competent host is supplemented with novel features that may increase its competitiveness. In addition, genetic ‘side effects’ raise food‐safety issues; and the possibility that they may sometimes increase ecological competitiveness cannot be ruled out, though this would be quite rare. Field plots have a proper use: to gather particular data that could be used in analysing the risks of commercial releases. But it is not scientific to call a small, confined, field population, isolated from potential competitors, a ‘test or release’ and then conclude that because ‘nothing happened’ the GEO will be safe when commercialized, or indeed that all

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00036.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractDrawing on field studies of pollen dispersal, we identify features of the hybridization process that need quantification. Our emphasis is on standardized measures, as opposed to the idiosyncratic and often anecdotal methods with which gene flow or out‐crossing data are currently reported. In addition to proposing specific maximum likelihood approaches, we summarize some results to date from small‐scale field trials that bear on the risks anticipated for large‐scale commercialization. We conclude that absolute containment of recombinant pollen or genes is unlikely if physical isolation is the only containment strategy. Because we conclude that the escape of transgenic pollen is inevitable, we argue that the focus of risk analysis should be shifted towards the ‘invasiveness’ of transgenic plants and ‘mitigation’ of their impact on natural, as well as agricul

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00037.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractTransgenes introduced into crops can escape in time, as well as space, via the seed bank. For annual plants, especially ruderals, seed bank behaviour may be the most important factor determining population persistence. Crop seeds may exhibit some dormancy and germination cueing in the soil but are expected to be less able to persist than their wild relatives, which often have considerable dormancy and longevity, as well as effective germination cueing responses. Crop‐wild hybrids may have seed bank characteristics more suited to persistence, and maternal effects may favour persistence of hybrids having wild plants for their female parent. Escape of transgenes via crop‐wild hybrids presents unique concerns not present for crops. Hybrids can undergo natural selection and may back‐cross with wild plants. We suggest methods that can be used in conjunction with evaluation of the relative fitness of crop‐wild hybrids that will determine the likelihood of back‐crossing. Accurate assessment of escape in time and transgene persistence via crop‐wild hybrids requires proper plant materials. We emphasize the use of null segregants as controls for transgenic crops and for generating crop‐wild hybrid controls for transgenic hybrids. Since good empirical and theoretical understanding of how individual genes influence the fate of plants in different environments is lacking, evaluation of escape in time and the persistence of transgenes via crop‐wild hybrids should be on a cas

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00038.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractFactors influencing the fate and impact of hybrids between crop plants and their related species operate from the early zygote, through to plant establishment in different habitats, to their ability to form self‐sustaining populations. Many of the classes of genes being introduced by modern methods of genetic modification are similar to those manipulated by conventional plant breeding. In assessing the impact of transgenes in hybrids between crops and related species, therefore, it is important to be informed about the consequences of hybridization between conventionally bred varieties and their relatives. Some transgenes will have novel effects (e.g. production of pharmaceutical substances or certain fatty acids) on plants, and are likely to need specific assessment studies to determine their impact on hybrids. This will be particularly important if there is the possibility of these transgenes becoming established in wild populations. Some recommendations for further research are outline

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00039.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractAssessing the impact of hybrids between transgenic plants and nontarget wild species involves answering several questions such as: (i) what are the hybridization and introgression rates; (ii) what is the behaviour of a transgene in a wild population; and (iii) what will be the consequences of the expression of a transgene in a wild population? These issues are discussed using results from experiments on oilseed rape and wild related Brassiceae. Evidence is given of large variations in the estimates of cross‐fertilization probabilities. The first stage of introgression into wild populations is demonstrated to occur spontaneously through back‐crossing. Population analysis may also be valuable to detect traces of past introgression. Data from the literature on weed biology, and especially herbicide resistance, are used to illustrate the behaviour of a new gene in weed populations. The need for computer models simulating the introgression process is stres

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00040.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryForces affecting the rate of spread and increase of hybrids between genetically modified crop plants and their related species remain qualitatively similar, irrespective of whether genetic modification was achieved using traditional methods, those of biotechnology or as a result of the natural evolutionary process. However, the precise magnitude of the forces and, consequently, the likely environmental impact of such hybrids, may depend strongly on the nature of the gene or genes introduced into the native species. While many classes of transgenes are similar to those manipulated by conventional breeding techniques or evolution, biotechnology offers the potential to introduce genes into crops which are novel both from the point of view of function and origin. The qualitative similarity between transgenes and the products of conventional or evolutionary modification suggests that a historical view of the environmental impact of hybrids between traditionally produced crops or exotic species and their relatives would be of use in estimating the probable fate of hybrids containing transgenes in the environment. However, with certain classes of transgenes for which there are no existing analogues, there will need to be greater care in assessing the possible risks associated with release into the environment.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00041.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractMany transgenic plant gene products introduced into soil are likely to degrade so quickly that they will have little impact upon the ecosystem. Some products, however, will be more recalcitrant and thus may exhibit potentially adverse effects upon the soil ecosystem. Potential changes in specific groups of organisms, functional groups of organisms and biodiversity are discussed. Methods to detect changes and the impact of changes are considered.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00042.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00043.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractLittle is known about the impact of transgenic plant products on soil organisms. However, previous research with synthetic organics, allelochemicals, and extracellular enzymes can be used to guide future research in this area. Projects designed to quantify the impact of transgenic plants on soil organisms must clearly establish that the gene products are responsible for any observed changes. This can only be achieved by determining the fate of transgenic plant gene products during the period of the soil bioassay. The overall impact of transgenic plants will be dictated by not only the primary gene product, but secondary products resulting from abiotic and biotic soil reactions. Primary and secondary products may exhibit both acute and chronic impacts. Such impacts are best quantified using a soil microcosm in which fungal populations and micro‐ and mesofauna are monitore

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00044.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY