World Wildlife Day:

Dreams & nightmares of genetically engineering wildlife.

Why conservation organisations across the world need to speak up!

Most people in the EU – including civil society organisations – are opposed to genetically manipulating food crops but unaware that the scope of genetic engineering projects has shifted radically in the past decade. With the advent of CRISPR/Cas genetic engineering has been brought to a new level while the previously used ‘gene guns’ that enabled for example Monsantos pesticide resistant corn have become quite outdated. With CRISPR many more species – and not only domesticated ones – can be genetically modified in much more targeted and profound way.

Genetic engineering in conservation?

Impressed by these new possibilities molecular biologists and even some conservation organisations have started to dream of genetic engineering as the magic bullet for nature conservation. Invasive species in particular are subject to research projects which aim to develop so called gene drive organisms. Gene drives – a specific application of CRISPR/Cas-based genetic engineering – ensures that a genetically engineered trait will be inherited by 100% of all offspring of an organism. Gene drive organisms, once released into natural environments, are designed to mate with their wild relatives and make the genetic modification a prevalent trait in the wild population – across generations.

One of the main proponents for using gene drives for invasive species elimination is the conservation organisation called Island Conservation. They have a long record of removing non-native invasive predators – predominantly rodents that threaten birds – from tropical biodiverse islands such as Hawaii and Galapagos. To date, this has been done using conventional methods, but Island Conservation believes that other tools such as gene drives are required. For this reason, Island Conservation initiated the Genetic Biocontrol of Invasive Rodents (GBIRd) project, which is supported by seven universities and non-governmental organizations from the USA and Australia, to investigate the gene drive approach and associated questions.

Mice, squirrels, ferrets, wasps, fruit flies and toads are among the species on the wish to be removed from the ecosystems they invaded and harm. Gene drive developers want to simply add a gene drive to specific genes in the germ cells of these organisms that for example code for the sex of the offspring. This could have the effect that only male or female offspring would be born and the population of the locally undesired species would crash over the course of a few generations.

The first steps to develop a gene drive in mice was taken in 2019 at the University of California in San Diego, USA. This research showed, however, that CRISPR gene drives do not yet work well in mammals.

Have we learned any lessons? Does it make sense to fight invasive species with invasive GMO?

In Queensland, Australia, sugarcane farmers in the past had huge issues with beetles that would destroy their crops. In 1935 cane toads (originally from South America) were introduced to fight the beetles. The cane toads succeeded in suppressing the beetle population but turned into invasive species themselves. Now those toads are a plague and spread throughout Australia as they can poison their predators. Australia’s national scientific research agency (CSIRO) is leading research projects on the elimination of cane toads via gene drive. But who can be sure that with gene drive cane toads history is not going to repeat itself?

A similar approach is pursued by the Roslin Institute in the United Kingdom, where the invasive grey squirrel (imported from North America 150 years ago) has pushed back the native red squirrel and destroys trees and bird nests. The idea here is similar to the one in Australia: A gene drive could either render the offspring infertile or only offspring with one sex would be born.

As Dave Goulson, a professor of biology at Sussex University points out anecdotally:

We used to eat and persecute red squirrels as pests. We introduced grey squirrels because we thought they were cute. Then they spread and the reds started to decline, so we reversed our opinion, deciding that the reds were now cute and the greys should be killed.”

So would it be a good idea to eliminate the grey squirrel with a gene drive?  Here’s just one other idea: Researchers have found that reintroducing almost extinct native predators, such as the pine marten into the UK, would lead to a decline of the grey squirrel and a rise of the red squirrel.

Early warnings: gene drives not suitable for conservation purposes

When New Zealand initially considered to include gene drives as part of their Preditor Free Program to rid the island of invasive species, two gene drive developers in 2017 published an article warning against such a decision.

They warned, that once released, the gene drive organisms, for example mice, could remain on the island for several years. Seen that only a few of these gene drive mice would be needed to infect a whole population, their long existence on the island could enable them to “hitch a ride” to other places.

If we have learned anything from the spread of invasive species, it is that ecosystems are connected in myriad ways and that a handful of organisms introduced in 1 country may have ramifications well beyond its own borders.”

They also warned that, even if these gene drive mice would not manage to leave the country by travelling along via tradeships or planes, experiences in the field of biocontrol seem to suggest that changes are high that they could be moved deliberately to countries where mice pose high damage to certain industries. For example, in the US alone the total cost of annual losses to rats amounts to US19 billion.

The two authors add, that as gene drive organisms are invasive by design, a handful of escaping rats from islands such as New Zealand to the main land would suffice to eliminate all rat populations, thereby severely damaging ecosystems and biodiversity worldwide. In addition, according to these authors, even developing gene drive organisms in labs within an area where the target species lives is dangerous, as any escape would be fatal.

The way forward: A bigger debate & a global moratorium is needed!  

In view of the possibility of using gene drives to remove introduced invasive species from sensitive ecosystems, the International Union for Conservation of Nature (IUCN), has also been discussing this technology since late 2015.

In its Members Assembly at its World Conservation Congress in Marseille in September 2021, the IUCN adopted Resolution 075 that mandates the IUCN to undertake an inclusive and participatory member-driven process to explore the role of genetic engineering and synthetic biology in relation to nature conservation. Based on this exploration, Resolution 075 asks the IUCN to develop a policy on this topic until its next World Congress in 2025.

This process will be an important opportunity for the global conservation scene to learn about these new developments. This process will hopefully provide a space to understand that there are many unanswered questions, knowledge gaps, risks and unassessed ecological aspects, conceptual and legal challenges as well as wider questions such as socio-economic, cultural, ethical and legal impacts associated with the genetic engineering of wildlife that need to be addressed before the IUCN can take a position. This position will send an important message to the ongoing regulatory discussions on the level of the UN CBD.

In the meantime the Stop Gene Drive Campaign is demanding national goverments across the world to impose a global moratorium on the environmental release of (including field trials with) gene drive organisms – as long as these open questions have not been answered and a global consensus on the use of this technology has not be reached.


Read here more about how gene drives work, their risks, about the IUCN discussions, the current state of gene drive regulation and our policy recommendations.