The EU not ready for the release of Gene drive organisms into the environment

Gene drive organisms (GDOs) have been suggested as an approach to solve some of the most pressing environmental and public health issues. Currently, it remains unclear what kind of regulations are to be used to cover the potential risks. In their study, published in the open-access journal BioRisk, scientists evaluate the options for an operational risk assessment of GDOs before their release into environments across the EU.

EU scientists are taking a closer look into the CRISPR/Cas-9-induced population-wide genetic modifications before introducing it into practice

Within the last decades, new genetic engineering tools for manipulating genetic material in plants, animals and microorganisms are getting large attention from the international community, bringing new challenges and possibilities. While genetically modified organisms (GMO) have been known and used for quite a while now, gene drive organisms (GDO) are yet at the consideration and evaluation stage. 

The difference between these two technologies, where both are meant to replace certain characters in animals or plants with ones that are more favourable for the human population, is that, even though in GDO there is also foreign “synthetic” DNA being introduced, the inheritance mode differs. In GDO, the genome’s original base arrangements are changed, using CRISPR/Cas-9 genome editing. Once the genome is changed, its alterations are carried down the organism’s offspring and subsequent generations. 

In their study, published in the open-access journal Biorisk, an international group of scientists led by Marion Dolezel from the Environment Agency Austria, discuss the potential risks and impacts on the environment. 

The research team also points to current regulations addressing invasive alien species and biocontrol agents, and finds that the GMO regulations are, in principle, also a useful starting point for GDO.

There are three main areas suggested to benefit from gene drive systems: public health (e.g. vector control of human pathogens), agriculture (e.g. weed and pest control), environmental protection and nature conservation (e.g. control of harmful non-native species).

In recent years, a range of studies have shown the feasibility of synthetic CRISPR-based gene drives in different organisms, such as yeast, the common fruit fly, mosquitoes and partly in mammals. 

Given the results of previous research, the gene drive approach can even be used as prevention for some zoonotic diseases and, hence, possible future pandemics. For example, laboratory tests showed that release of genetically modified mosquitoes can drastically reduce the number of malaria vectors. Nevertheless, potential environment and health implications, related to the release of GDO, remain unclear. Only a few potential applications have so far progressed to the research and development stage.

“The potential of GDOs for unlimited spread throughout wild populations, once released, and the apparently inexhaustible possibilities of multiple and rapid modifications of the genome in a vast variety of organisms, including higher organisms such as vertebrates, pose specific challenges for the application of adequate risk assessment methodologies”,

shares the lead researcher Mrs. Dolezel.

In the sense of genetic engineering being a fastly developing science, every novel feature must be taken into account, while preparing evaluations and guidances, and each of them provides extra challenges.

Today, the scientists present three key differences of gene drives compared to the classical GMO:

1. Introducing novel modifications to wild populations instead of “familiar” crop species, which is a major difference between “classic” GMOs and GDOs.

“The goal of gene drive applications is to introduce a permanent change in the ecosystem, either by introducing a phenotypic change or by drastically reducing or eradicating a local population or a species. This is a fundamental difference to GM crops for which each single generation of hybrid seed is genetically modified, released and removed from the environment after a relatively short period”,

shares Dolezel.

2. Intentional and potentially unlimited spread of synthetic genes in wild populations and natural ecosystems.

Gene flow of synthetic genes to wild organisms can have adverse ecological impact on the genetic diversity of the targeted population. It could change the weediness or invasiveness of certain plants, but also threaten with extinction the species in the wild.

3. Possibility for long-term risks to populations and ecosystems.

Key and unique features of GDOs are the potential long-term changes in populations and large-scale spread across generations. 

In summary, the research team points out that, most of all, gene drive organisms must be handled extremely carefully, and that the environmental risks related to their release must be assessed under rigorous scrutiny. The standard requirements before the release of GDOs need to also include close post-release monitoring and risk management measures.

It is still hard to assess with certainty the potential risks and impact of gene drive applications on the environment, human and animal health. That’s why highly important questions need to be addressed, and the key one is whether genetically driven organisms are to be deliberately released into the environment in the European Union. The High Level Group of the European Commission’s Scientific Advice Mechanism highlights that within the current regulatory frameworks those risks may not be covered.

The research group recommends the institutions to evaluate whether the regulatory oversight of GMOs in the EU is accomodate to cover the novel risks and challenges posed by gene drive applications.

“The final decision to release GDOs into the environment will, however, not be a purely scientific question, but will need some form of broader stakeholder engagement and the commitment to specific protection goals for human health and the environment”,

concludes  Dolezel.

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Original source:
Dolezel M, Lüthi C, Gaugitsch H (2020) Beyond limits – the pitfalls of global gene drives for environmental risk assessment in the European Union. BioRisk 15: 1-29. https://doi.org/10.3897/biorisk.15.49297

Contact:
Marion Dolezel
Email: marion.dolezel@umweltbundesamt.at

Experiment suggests the best ways to tackle invasive Oregon grape in Belgian coastal dunes

The Belgian coastal dunes, a protected habitat of high conservation value, are getting severely impacted by one of its worst enemies amongst invasive species: the Oregon grape. To help mitigate the detrimental effect of this North American shrub invader, Belgian scientists carried out an experiment to assess the effectiveness of different management methods.

The Belgian coastal dunes, a protected habitat of high conservation value, are getting severely impacted by one of its worst enemies amongst invasive species: the Oregon grape. To help mitigate the detrimental effect of this North American shrub invader, Belgian scientists carried out an experiment to assess the effectiveness of different management methods.

The Atlantic coastal dunes form a dynamic and diverse ecosystem, home to a large number of native species, many of which are regionally threatened. Embryonic dunesshifting white dunes, moss dunes, dune grasslands, and dune slacks are considered high conservation value sites, according to the interpretation manual of European habitats. However, the dunes are highly affected by external influences, and one of the most important threats to their biodiversity are invasive non-native plant species. These plants often colonised the dunes as garden escapes or spread from garden waste dumps or public plantings. Oregon grape is one of the worst invaders amongst them.

Oregon grape growing on sand dune (Belgium).
Photo by Tim Adriaens.

In their study, published in the open-access journal NeoBiota, the scientists, led by Tim Adriaens and Sam Provoost of the Research Institute for Nature and Forest (INBO), focus on the management of the current populations of Oregon grape (Berberis aquifolium) in the Belgian coastal dunes, where the species has already managed to invade half of the 46 nature reserves and is starting to replace native vegetation. Such a negative effect on the biodiversity of the area requires practical management advice. Due to the high level of infestation of the dunes, the researchers recommend prompt eradication as the most appropriate management strategy. So far, however, it has been unclear which method would show the best effectiveness.

“Invasive shrub species exert an additional pressure on Belgian dune ecosystems, which are already highly fragmented by urbanisation. Oregon grape is one of the worst and should be tackled urgently before it gets out of control,” says Tim Adriaens.

Having compared four previously suggested treatments: manual uprooting, foliar herbicide application, stem cutting followed by herbicide and salt application, the scientists reported herbicide leaf treatment to be the most effective method. Manual removal by digging and treating stems with glyphosate showed medium effectiveness. Treating stems with a saturated salt solution appeared rather cosmetic. However, it’s not that easy to choose which method would be the best to work with, since with herbicide use there are non-target effects on the environment, economy, and society to be considered.

Dune restoration by mechanical removal of dense Oregon grape infestation (left) and leaf treatment of Oregon grape clone with a hand sprayer (right).
Photo by Tim Adriaens.

“Individual clones are best treated with herbicide, large surface areas provide opportunities for landscape-scale ecological restoration, combining invasive shrub removal with sand dune creation,” further explains Tim Adriaens.

In Belgium, Oregon grape was first recorded in the wild in 1906 and naturalised in the period 1920-1950. It has been spreading rapidly since the 1990s. This expansion might be linked to cultivated hybrids and global warming, with the latter leading to a lengthened growing season, suggest the scientists. The species likes calcareous soils. Along the Belgian coast, Oregon grape has mainly invaded grey dunes, scrub and woodland.

Thanks to its numerous blue berries, which are easily dispersed over long distances by songbirds, the plant can appear everywhere within the dunes sites, also in places hardly accessible to managers. With the help of a highly branched root system, the plants attach themselves firmly in the sand, which makes manual pulling of mature plants hardly possible and labor-intensive.

“Dune managers and scientists across Europe should unite to draft alert lists and prioritise established alien species for management,” Tim says in conclusion.

In conclusion, the scientists highlight the importance of an EU-wide collaboration between scientific communities. Invasive species are not bothered by administrative borders and exchanging experiences on impact and management options is crucial to maintain dune ecosystems in good conservation status.

Coastal dunes in Belgium provide unique habitat to many Red listed species.
Photo by Tim Adriaens.

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Original source

Adriaens T, Verschelde P, Cartuyvels E, D’hondt B, Vercruysse E, van Gompel W, Dewulf E, Provoost S (2019) A preliminary field trial to compare control techniques for invasive Berberis aquifolium in Belgian coastal dunes. NeoBiota 53: 41-60. https://doi.org/10.3897/neobiota.53.38183