Work on engineered gene used to modify DNA of mosquitoes ‘could be stifled’ by perceived risk to environment

Research on a radical new way to combat malaria and other devastating diseases could be knocked off track if a UN biodiversity conference imposes a moratorium on the work, a group of scientists have said.

Some scientists believe the different approach has the potential to transform the battle against malaria. It involves engineered gene drives which are used to modify the DNA of wild organisms on a mass scale. In the case of mosquitoes the method would have the potential to wipe out populations of certain species which carry the malaria parasite, say the scientists.

Critics have argued that gene drives pose an unacceptable risk by spreading modified genes through the environment with unpredictable consequences.

The UN’s convention on biological diversity (CBD) meeting in Egypt next week will consider recommendations that call on governments to refrain from releasing organisms that contain gene drives, even in small-scale field trials.

The wording has prompted more than 100 scientists to sign an open letter opposing the proposal. If adopted, they believe, the move would stifle gene drive work across the board, because field trials were crucial for understanding whether the technology worked in the wild.

“We should not decide against the use of a tool before potential costs and benefits can be fully evaluated,” the letter stated.

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Gene drives come in many different forms but all are designed to ramp up the presence of engineered genes in a target population of organisms. One method creates modified mosquitoes in the laboratory which, when released, breed with wild mosquitoes and pass on a mutated gene that renders the females sterile. As a result the population crashes.

Under the normal rules of inheritance, modified mosquitoes that mate with the wild insects would pass on the mutated gene only 50% of the time – because offspring inherit half of their genes from each parent. A gene drive achieves nearly 100% inheritance rates by replacing the gene from the wild parent with a mutated version.

Austin Burt, a researcher at Imperial College London, who works on gene drives to tackle malaria, said a moratorium such as the one suggested would “stifle research and be a huge distraction”.

He said: “It’s such a new field that there isn’t even agreement on what a gene drive is. To say all of them, in all organisms and in all environments, are unsafe is meaningless. We already have mechanisms for assessing them. To judge safety you have to do things on a case-by-case basis, you have to know the exact organism, the exact construct, and the exact environment.”

There are more than 3,500 species of mosquitoes, but only the females of about 40 species belonging to the genus Anopheles transmit malaria well enough to cause significant illness and death in humans. The disease kills more than 400,000 people a year, mostly children in Africa, and infects more than 200 million.

Fredros Okumu, a director of science at the Ifakara Health Institute in Tanzania, said that while gene drives carried potential risks they should not be ruled out.

He said: “For the first time we have a tool that requires minimal human compliance, a minimal health system, and which would work even in difficult to reach areas because mosquitoes will spread it by themselves.

“We are not saying this is ready for deployment. But the truth is we really need something that gives us the oomph to remove this disease, especially in places in Africa that struggle with health systems. Even if there is some risk we should allow scientists to investigate them rather than say don’t go there.”

Jim Thomas, at the ETC Group, an NGO that opposes gene drives, claimed that more than 200 organisations, networks and individuals from the global food movement supported a ban on releasing the drives into the environment. He argued that the letter, organised by a PR agency, appeared to serve scientists with a professional interest.

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Thomas also raised concerns about how gene drives would be used in agriculture. In principle, a gene drive could make entire fields of crops drought resistant, or wipe out all weeds. In a recent report the group claimed the approach could undermine sustainable and equitable food and agriculture.

Joyce Tait, co-director of the Innogen Institute, at the University of Edinburgh, who has not signed the letter, said: “It is widely seen as bad practice to attempt to ensure the safety of innovative developments by focusing on the technique used to produce them – in this case a gene drive – than on the properties of the end product itself.

“Some applications of gene drives will be benign, others will be potentially hazardous, and treating them all equally undermines the principle of evidence-based decision making.”

Robin Lovell-Badge, chair of the Royal Society’s genetic technologies programme, said: While much can be learned about specific gene drives in strictly controlled laboratory settings, it will be critically important to continue the research by carrying out field trials … without the ability to carry out field trials the best scientists are less likely to get involved in any of the research, funders would lose interest, and we could miss out on important ways to reduce the burden of disease and to restore compromised environments to a more original state.”