How changes in DNA strands can self-destruct mosquitoes that spread malaria

For the first time, scientists have shown that a new type of genetic engineering can destroy a population of mosquitoes that spread malaria.

At a landmark studyPublished in the journal on Wednesday Nature CommunicationsResearchers have placed genetically modified mosquitoes in a special laboratory that simulates the situation in sub-Saharan Africa, where they have spread a deadly disease.

Male mosquitoes have been designed with a series of DNA known as “gene drives” that can rapidly transmit harmful mutations that essentially wipe out insect populations.

The goal is to create a powerful new tool for fighting malaria, one of the most horrific tragedy in the world.

“Our research is the first [that] We can show that gene drive technology works under ecologically difficult conditions. ” Ruth Muller, The entomologist who led the study PoloGGB, High security lab in Terni, Italy. “This is a big step forward in our research.”

This study is supported by NPR and the Bill & Melinda Gates Foundation, which sponsors this blog.

Years of additional research are required to prove that the approach works and that mosquitoes are safely released into the wild. The project also requires regulatory approval and agreement by residents of these mosquito-dwelling areas, primarily sub-Saharan Africa and some parts of Asia.

Despite years of effort, malaria remains a major health problem. Mosquito-borne parasitosis affects more than 200 million people each year, kills more than 400,000, and many are children.

So Muller and her colleagues decided to use CRISPR, a technique that makes it easy for scientists to make very precise changes to DNA to make genetic modifications. Anopheles gambie A mosquito species that spreads malaria in sub-Saharan Africa.

The modification consisted of a mutation in a gene known as “double sex” that female mosquitoes require for normal development. Mutations deform their mouths, preventing them from chewing and spreading parasites. It also deforms the reproductive organs and makes it impossible to lay eggs.

Mutations are combined with gene drives and are described as “effectively a selfish type of genetic component that spreads across mosquito populations.” Tony Nolan Of the Liverpool Tropical Medicine School, who helped develop and test mosquitoes.

Researchers have taken special steps to prevent insects from escaping, as they can upset the delicate balance of the ecosystem. Scientists first tested mosquitoes in a safe basement in London, where Mosquitoes destroyed unmodified mosquitoes in a small cage..

To safely test mosquitoes under more natural conditions, researchers have built a special high-security lab in Italy designed to keep gene-driven mosquitoes from escaping. For example, anyone entering the safest part of the laboratory had to go through a special room to keep out mosquitoes. For some reason, the lab was intentionally placed far away from Africa in case the mosquitoes managed to escape.

After that, the researchers Dozens of gene-drive mosquitoes were released into special large cages containing hundreds of natural mosquitoes. Unlike the smaller cages in London, the Italian cages were much larger, mimicking the sub-Saharan African environment in terms of temperature, humidity, and even the timing of sunrise and sunset.

Gene-drive mosquitoes reduced the natural mosquito population within a year, the study authors reported.

Other researchers welcome progress.

“It’s a step in the right direction,” he says. Anthony JamesHe is a professor of microbiology and genetics at the University of California, Irvine, and is conducting similar research. “It’s very important.”

“In my opinion, the use of gene-drive mosquitoes is effective against the spread of malaria and other carrier-borne diseases,” he said. Jeantine Lunshof, A bioethicist at the Wyss Institute for Biologically Inspired Engineering at Harvard University.

“I think the benefits of it are enormous, and I haven’t found a compelling argument that this would have a significant detrimental effect,” she says.

Others are very skeptical and say the technology is too dangerous.

“The idea of ​​a gene drive mosquito is very disturbing to me and the many people I talk to,” he says. Nnimo BasseyLeads the Health of Mother Earth Foundation in Nigeria, an environmental organization. “It can upset the balance of our ecosystem,” in an unpredictable way.

“This experiment reminds us that there is no safe and ethical way to experiment with gene drives,” he wrote. Dana Pearls E-mail to NPR of the Environmental Group Friends of the Earth. “You have to press the pause button for gene-driven organisms until strong international preventive regulation and surveillance takes place.”

Copyright 2021 NPR. For more information, please visit https://www.npr.org.

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