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

Mosquito populations give a new insight into the role of Caucasus in evolution

We know that the Caucasus is a relatively large mountainous region, situated between Black and the Caspian seas. In its turn, it is divided into three subregions: Ciscaucasia, Greater Caucasus and Transcaucasia, also known as South Caucasus.

A closer look into the chromosome structure of mosquito larvae of a curious group of species (Chironomus “annularius” sensu Strenzke (1959)), collected from the three localities, has allowed Dr Mukhamed Karmokov of the Tembotov Institute of Ecology of Mountain territories at the Russian Academy of Science to figure out how the specificity of the Caucasian region has simultaneously unified its fauna geographically, yet has divided it evolutionarily. His paper is published in the open access journal Comparative Cytogenetics.

Having collected a sufficient amount of mosquito larvae, the researcher managed to study the chromosome structure, rearrangements and possible peculiarities of the separate Caucasian populations, in order to compare them.

Additionally, he analysed their relations to earlier known populations from Europe, Siberia, Kazakhstan and North America.

Amongst the curious peculiarities Karmokov identified in the chromosome structure of the studied larvae were some rearrangements which appear unique to Caucasus. Furthermore, he found that despite the close geographic proximity, the genetic distance between the Caucasian populations is quite significant, even While not enough to determine them as separate species, it could prove them as separate subspecies.

In conclusion, the scientist notes that the obtained data confirm that the Caucasian populations of the studied species have complex genetic structure and provide evidence for microevolution processes in the region.

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Original source:

Karmokov MKh (2018) Karyotype characteristics and chromosomal polymorphism of Chironomus “annularius” sensu Strenzke (1959) (Diptera, Chironomidae) from the Caucasus region. Comparative Cytogenetics 12(3): 267-284. https://doi.org/10.3897/CompCytogen.v12i3.25832

New butterfly species discovered in Russia with an unusual set of 46 chromosomes

What looked like a population of a common butterfly species turned out to be a whole new organism, and, moreover – one with a very peculiar genome organisation.

Discovered by Vladimir Lukhtanov, entomologist and evolutionary biologist at the Zoological Institute in St. Petersburg, Russia, and Alexander Dantchenko, entomologist and chemist at the Moscow State University, the startling discovery was named South-Russian blue (Polyommatus australorossicus). It was found flying over the northern slopes of the Caucasus mountains in southern Russia. The study is published in the open access journal Comparative Cytogenetics.

“This publication is the long-awaited completion of a twenty-year history,” says Vladimir Lukhtanov.

In the mid-nineties, Vladimir Lukhtanov, together with his students and collaborators, started an exhaustive study of Russian butterflies using an array of modern and traditional research techniques. In 1997, Alexander Dantchenko who was mostly focused on butterfly ecology, sampled a few blue butterfly specimens from northern slopes of the Caucasus mountains. These blues looked typical at first glance and were identified as Azerbaijani blue (Polyommatus aserbeidschanus).

However, when the scientists looked at them under a microscope, it became clear that they had 46 chromosomes – a very unusual number for this group of the blue butterflies and exactly the same count as in humans.

Having spent twenty years studying the chromosomes of more than a hundred blue butterfly species and sequencing DNA from all closely related species, the researchers were ready to ascertain the uniqueness of the discovered butterfly and its chromosome set.

Throughout the years of investigation, it has become clear that caterpillars of genetically related species in the studied butterfly group feed on different, but similar plants. This discovery enables entomologists to not only discover new butterfly species with the help of botanic information, but also protect them.

“We are proud of our research,” says Vladimir Lukhtanov. “It contributes greatly to both the study of biodiversity and understanding the mechanisms of biological evolution.”

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Original source:

Lukhtanov VA, Dantchenko AV (2017) A new butterfly species from south Russia revealed through chromosomal and molecular analysis of the Polyommatus (Agrodiaetus) damonides complex (Lepidoptera, Lycaenidae). Comparative Cytogenetics 11(4): 769-795. https://doi.org/10.3897/CompCytogen.v11i4.20072