INRA, UAR 1240 Eco-Innov, Avenue Lucien Brétignières, 78850, Thiverval-Grignon, France.
Transgenic Res. 2012 Apr;21(2):243-56. doi: 10.1007/s11248-011-9527-5. Epub 2011 Jun 17.
To respect the European labelling threshold for the adventitious presence of genetically modified organisms (GMOs) in food and feed, stakeholders mainly rely on real-time PCR analysis, which provides a measurement expressed as a percentage of GM-DNA. However, this measurement veils the complexity of gene flow, especially in the case of gene stacking. We have investigated the impact of gene stacking on adventitious GM presence due to pollen flow and seed admixture as well as its translation in terms of the percentage of GM-DNA in a non-GM maize harvest. In the case of varieties bearing one to four stacked events, we established a set of relationships between the percentage of GM kernels and the percentage of GM-DNA in a non-GM harvest as well as a set of relationships between the rate of seed admixture and the percentages of GM material in a non-GM harvest. Thanks to these relationships, and based on simulations with a gene flow model, we have been able to demonstrate that the number of events and the stacking structure of the emitting fields impact the ability of a non-GM maize producer to comply with given GM kernel or GM-DNA thresholds. We also show that a great variability in the rates of GM kernels, embryos and DNA results from seed admixture. Finally, the choice of a unit of measurement for a GM threshold in seed lots can have opposite effects on the ability of farmers to comply with a given threshold depending on whether they are crop or seed producers.
为了尊重食品和饲料中转基因生物体（GMO）偶然存在的欧洲标签阈值，利益相关者主要依赖实时 PCR 分析，该分析提供了以 GM-DNA 百分比表示的测量值。然而，这种测量掩盖了基因流动的复杂性，特别是在基因堆叠的情况下。我们研究了由于花粉流动和种子混合导致的基因堆叠对偶然 GM 存在的影响，以及其在非 GM 玉米收获中 GM-DNA 百分比方面的转化。对于携带一个到四个堆叠事件的品种，我们建立了一组 GM 内核百分比与非 GM 收获中 GM-DNA 百分比之间的关系，以及一组种子混合率与非 GM 收获中 GM 物质百分比之间的关系。基于这些关系，并通过基因流动模型进行模拟，我们能够证明事件数量和发射场的堆叠结构会影响非 GM 玉米生产者遵守给定 GM 内核或 GM-DNA 阈值的能力。我们还表明，种子混合会导致 GM 内核、胚胎和 DNA 的比率存在很大差异。最后，根据他们是作物还是种子生产者，用于种子批次 GM 阈值的测量单位的选择可能会对农民遵守给定阈值的能力产生相反的影响。
