Genetically-Altered Mosquitoes May Be Key to Eradicating Malaria, Study Shows
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Malaria continues to devastate: More than 40 percent of the global population lives in areas where there is the risk of contracting the disease, which killed an estimated half a million people in 2013.
Spread via infected mosquito, the disease has proven impossible to eliminate with existing strategies.
But researchers at the University of California -- including Anthony James, a professor of molecular biology and biochemistry -- have developed a possibly groundbreaking new tool in the fight to eradicate the disease. A paper published today in the scientific journal PNAS details their attempt at introducing malaria-blocking genes into the DNA of disease-transmitting mosquitoes.
While James has been working for nearly two decades on ways to alter mosquito populations, this latest attempt is different. Notably, it uses CRISPR (pronounced “crisper”), the recently discovered gene-editing technique that is cheaper, faster, more flexible and in many ways more precise than alternative methods. And crucially, it is able to alter both dominant and recessive marker genes -- to huge results.
In James's previous work, which has focused on injecting mosquitoes with synthetic DNA to combat the spread of dengue fever, the modification was only passed down to its offspring 50 percent of the time because it was carried by only one of a pair of chromosomes. But in the PNAS study, when malaria-blocking genes were inserted into a population of Anapheles mosquitoes using CRISPR, the modification could be copied to the partner chromosome and thus passed down in every generation. As a result, inheritance rates rose to 99.5 percent.
"This opens up the real promise that this technique can be adapted for eliminating malaria," James said in a statement. "This is a significant first step. 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."
In a homogenous mosquito population, the gene mutation would spread throughout the entire population in 10 generations (or around three months), says Valentino Gantz, one of the study's authors. If it sounds remarkably fast, it is. While methods for altering mosquito DNA in an attempt to control disease have been around for years, none have shown to be as efficient or effective, says Gantz.
"CRISPR technology is just a different way to do the same thing other people have done before. But in this case, it appears to work much better."