Weeds in the campaign

First scientific review of risks due to offspring of GE plants persisting in natural populations

A new peer-reviewed paper (see abstract below) published in the international journal Environmental Sciences Europe addresses specific environmental risks associated with genetically engineered (GE) plants that can spread and propagate in the environment. It is the first publication that focuses on on the risk assessment of so-called next generation effects. The review examines unintended effects that were observed in spontaneous hybrid offspring but absent in the original plants. Some of the risks include a higher invasive potential of the GE plants and/or disruption of the associated ecosystems.

Christoph Then of Testbiotech, one of the authors, commented, “If gene flow to natural populations cannot be prevented, this can put biodiversity and the livelihoods of future generations at risk. These risks concern the cultivation of GE plants such as oilseed rape in the US, Canada and Australia; camelina in the US; rice in Asian countries and cowpeas in Africa. There is also a risk caused by import of GE plants for the EU if, for example, spillage occurs during transport from viable kernels of GE oilseed rape. Plants growing from these kernels can survive in the environment and spread uncontrollably.”

In many cases the observed effects in the hybrid generations were not predictable from the first generations of the genetically engineered plants. They include a higher amount of seeds or pollen, enhanced stress resistance, and changes in other biological characteristics of the GE plants. The reasons are diverse, including environmental stress factors as well as genomic interactions in the hybrid offspring.

In view of these findings, the authors suggest the introduction of new ‘cut-off criteria’ in risk assessment that explicitly address the spatio-temporal control of GE organisms. If the criteria are not fulfilled, the environmental release cannot be permitted.

“This additional step in risk assessment is becoming increasingly important as research is ongoing to develop, e.g. gene drives in GE insects that can persist and propagate in the environment. These projects could pose a major threat to nature conservation in the future,” said Christoph Then.

The paper was published to follow up the international RAGES research project (Risk Assessment of Genetically Engineered organisms in the EU and Switzerland) which was carried out between 2016 and 2019.

RAGES was carried out independently of the biotech industry and funded by Mercator Switzerland. The project provides strong evidence that contrary what is claimed by industry, the risks of genetically engineered plants are not sufficiently investigated. Against the backdrop of this new research, Testbiotech is particularly concerned about a possible EU-US trade deal which aims to speed up the approval process for GE organisms in the EU and threatens the precautionary principle as a foundation of EU policy making. According to media, there are plans to take first decisions as soon as mid-March.

Further information:

The results from RAGES:
Report about the planned new trade agreement with the US:

Source: Testbiotech

Risk assessment of genetically engineered plants that can persist and propagate in the environment
Andreas Bauer-Panskus, Juliana Miyazaki, Katharina Kawall & Christoph Then
Environmental Sciences Europe volume 32, Article number: 32 (2020)


New challenges arise in risk assessment when genetically engineered (GE) plants can persist and propagate in the environment as well as produce viable offspring. Next generation effects can be influenced by heterogeneous genetic backgrounds and unexpected effects can be triggered in interaction with environmental conditions. Consequently, the biological characteristics of the original events cannot be regarded as sufficient to conclude on hazards that may emerge in following generations. Potential hazards identified by the European Food Safety Authority (EFSA) include exacerbating weed problems, displacement and even extinction of native plant species. However, there are reasons for concern that might escape the environmental risk assessment (ERA) because EFSA only takes into account the characteristics of the original events, leaving aside unintended or unexpected next generation effects emerging from spontaneous propagation and gene flow. From our review of the publications available and the analysis of risk assessment as performed, we conclude that the risk assessment of GE organisms able to persist and spontaneously propagate in the environment actually suffers from a high degree of spatio-temporal complexity causing many uncertainties. To deal with this problem, we recommend establishing ‘cut-off criteria’ in risk assessment that include factual limits of knowledge. It is proposed that these criteria are applied in a specific step within risk assessment, i.e. ‘spatio-temporal controllability’ that uses well-defined biological characteristics to delineate some of the boundaries between known and unknowns. This additional step in risk assessment will foster robustness in the process and can substantially benefit the reliability and overall conclusiveness of risk assessment and decision-making on potential releases.