Mosquito DNA Edited to Prevent Malaria from Spreading New Scientist

By changing the gene, malaria mosquitoes die before the malaria parasites can develop in their bodies. That could completely stop the spread of the deadly parasite, according to lab research and computer modeling.

due to genetic modification Malaria parasites evolve less quicklyThe modification also shortens the lifespan of mosquitoes. As a result, they die before they can transmit the disease.

Laboratory studies and computer modeling suggest that this can completely stop the spread of the deadly parasite, according to George Christofides, Professor of Infectious Diseases and Immunology at Imperial College London and part of the research team. “The combination of these two effects will eliminate malaria transmission,” he says.

For this approach to work, something called gene compression must be used, which means it is necessary Gene editing It spreads in wild mosquito populations. Through this mechanism, all offspring inherit a particular piece of DNA, with only half of the offspring inheriting the DNA. Due to genetic pressure, this piece of DNA spreads to the entire population, even if the mutation has negative consequences for mosquitoes.

capturing

Synthetic gene printing has not been used in the wild, although natural copies exist. CRISPR-based gene pressure has already been successfully tested on mosquitoes in captivity.

Researchers in Tanzania are now modifying local mosquitoes, in the same way that the London researchers used, to see how effective the modification is against native malaria parasites. If these modifications prove successful, the teams will want to work together to conduct field trials. For now, they keep the tests inside the walls of the lab. “We don’t shoot anything,” Christofides says.

The new method is based on the fact that malaria parasites take between ten and twelve days to develop inside the mosquito’s body and reach the salivary glands. Only then can mosquito bites infect people. But living in the wild Anopheles The GambiaMosquitoes, which can carry malaria, usually only last for ten days.

protein vs parasite

“So you can disrupt the entire transmission cycle by slowing the growth of parasites,” Christofides says. To achieve this, his team set out to work on genetic modification in A Gambiamosquitoes, causing their intestinal cells to secrete two small proteins that have been shown to slow the parasite’s growth. One of these proteins comes from African clawed frogs, and the other from honeybees.

The team has already shown that it takes a few days longer for malaria parasites to be detected in infected and modified mosquitoes. The genetic change also shortens the lifespan of mosquitoes by a few days, Christofides says. This reduces the chance of the mosquito surviving long enough to become infective.

Evolution as an obstacle

There are two potential problems with this approach. As genetic pressure spreads the modification further, there is a risk that malaria parasites will develop resistance to the two proteins. To prevent this, it is important to disseminate the modification as widely as possible, says Christofides. The faster the parasite population collapses, the less chance there is for resistance to develop through evolution.

In addition, it is possible for mosquitoes to evolve in such a way that gene pressure no longer works. Christophides says it must be designed so that this risk remains minimal.

Other research groups are also working on other versions of genetic pressure that could wipe out mosquito populations, for example by making all female offspring sterile while males remain fertile and spread genetic pressure.

kill or be killed

You can also use these two approaches together. for the first time killer gene pressure, which wipes out the population in one area, followed by genetic pressure that prevents survivors or mosquitoes from other areas from spreading malaria. “We think they can contribute something,” Christofides says.

Millions of genetically modified male mosquitoes are already being released in Brazil to reduce the number of wild mosquitoes. This mosquito carries a gene that kills all offspring of the females with which it mates. There is no evidence yet that this gene persists in the wild for long periods of time.

Malaria still kills half a million people each year, mostly children. Last year was the malaria vaccine It was approved for the first time. This may follow soon after, but these vaccines are not equally effective in all cases.