0604 GMT December 07, 2019
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, said the scientists, according to The Guardian.
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.
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 percent of the time — because offspring inherit half of their genes from each parent. A gene drive achieves nearly 100 percent 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.