These genetically modified mosquitos could end malaria for good

Scientists from the Universities of California’s Irvine and San Diego campuses have come up with a way to potentially end the scourge of malaria—a disease the CDC estimates killed half a million people in 2013— with the genetically modification of mosquitoes.

According to CNN and Engadget, mosquitoes that spread malaria typically do so because they are infected with parasitic bacteria from the genus Plasmodium. Scientists were previously able to breed mosquitoes resistant to this bacteria, but in the new study, they discovered how to spread this resistance to the rest of a population through DNA manipulation.

As they explain in the latest edition of the Proceedings of the National Academy of Sciences, the authors used the CRISPR-9 gene editing technique to insert a pair of genes which are responsible for encoding resistance to the parasitic bacteria onto the chromosomes of an Anopheles stephensi mosquito, a known vector for the disease.

Their method guarantees that the genes will be passed along to offspring, and they reported a 99.5 percent success rate in spreading the resistance to future generations. If these mosquitoes were to be released into the wild, they said, the bacteria-resistant genes would spread much more quickly than the vulnerable genes, effectively keeping the bugs from spreading malaria to humans.

A ‘significant first step’ in the fight against the disease

Additional testing and possible large scale field studies are required, and the scientists emphasize that there are also ethical and regulatory obstacles to overcome before their approach can be used in real-world conditions. However, as they told CNN, this is a significant first step.

“This opens up the real promise that this technique can be adapted for eliminating malaria,” said Anthony James, a professor of molecular biology and biochemistry, as well as microbiology and molecular genetics, at UC Irvine. “We know the gene works. The mosquitoes we created are not the final brand, but we know this technology allows us to efficiently create large populations.”

James and his colleagues have been working on modifying mosquitoes in order to prevent them from spreading diseases for nearly two decades. In 2012, he demonstrated that antibodies from a mouse’s immune system that impair the biology of the parasite could be adapted and introduced into mosquitoes, but this trait would only be inherited by roughly half of future insects.

The new breakthrough comes with the help of UCSD biologists Ethan Bier and Valentino Gantz, who came up with a method to generate mutations in both copies of a gene in fruit flies using the CRISPR-associated Cas9 nuclease enzyme. The two groups joined forces and together developed a genetic “cassette” they injected into mosquito embryos to insert antimalaria antibodies.

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