Are mosquitoes with gene drive soon to be released in West Africa?

Scientists at London's Imperial College have successfully tested mosquitoes with gene drive in the laboratory. By using these genetically manipulated insects they succeeded in killing a cage full of mosquitoes.They now plan to release GM mosquitoes in Burkina Faso in West Africa to combat malaria.

A gene drive is a genetic engineering technology that enables a specifically inserted characteristic to be inherited in plants and animals and to be swiftly propagated throughout a population. Gene drives have so far been tested only in the laboratory, in particular with mosquitoes that spread dangerous diseases. It has been shown that populations gradually develop a certain resistance and find a way round the for them mostly deadly modification.

Financed by the Fates Foundation

The London scientists have now succeeded in avoiding this development of resistance. They modified a small section of the gene that in the case of mosquitoes regulates which sex emerges from the egg. They inserted genetic information that makes the females sterile and linked it with a gene drive. Within seven to eleven generations the number of eggs laid by the females was practically zero and the population died out. The researchers explained that the reason why the mosquitoes did not develop any resistance was the nature of the gene into which they inserted the sterility and gene drive. The gene in question is one whose DNA sequence has remained stable throughout evolution and was therefore well protected against mutations. This means that the mosquitoes' genome does not contain any similarly constructed copies that could take over its function and render the gene drive ineffective.

The research at Imperial College is financed principally by the Gates Foundation. It is an integral part of the foundation's Target Malaria project whose mission is to combat malaria using genetic engineering in Mali, Uganda and Burkina Faso. This summer the government of Burkina Faso authorised the project to release mosquitoes. The first stage involves mosquitoes that have been modified to render the males sterile – but not yet with gene drive. The media platform Telesur reported that this experiment is specifically designed to gain the trust of the people. Telesur wrote: “If this experiment is successful the scientists in Burkina Faso hope they can release special gene drive mosquitoes.”

About the risks involved in gene drive

In a comment the molecular biologist Ricarda Steinbrecher from the organisation EcoNexus draws attention to the risks involved in this kind of strategy. She points out that the protected gene being used occurs in all 16 species of Anopheles mosquitoes. She states that genetic exchange is known to occur between the different species and she concludes that a gene drive concealed in protected genes can spread across several species and exterminate them: “This new strategy adds further risks and doubts to a technique already considered to be high-risk technology.”

To comply with European law, Imperial College would have to submit a publicly accessible environmental compatibility test in keeping with European standards before it sends the eggs of genetically modified insects to Africa for release, the organisation Genewatch UK wrote in February 2018. Its argument is based on the guidelines of the Cartagena Protocol on Biosafety. This protocol is a part of the UN Convention on Biological Diversity that both Britain and Burkina Faso have ratified. According to GeneWatch, the guidelines also apply to the currently planned release of GM mosquitoes without gene drive. It states that to date no risk assessment has been produced.