California — Scientists of the University of California created genetically modified mosquitoes with malaria-blocking genes, also capable of passing these genes to their offspring. If the experiment succeeds, mosquitoes would become unable to infect humans with the disease.
Researchers followed the Crispr method, a gene-editing technique used to insert DNA into the nucleus of a cell in order to replace mutated genes or add new ones. Scientists used it to insert a DNA element into Anopheles stephensi mosquitoes. The malaria-blocking gene was then successfully passed onto almost a hundred percent of the mosquitoes’ offspring.
Malaria survives by using blood-feeding mosquitoes as hosts, since they’re suitable to pass the parasite into humans and animals every time they feed, quickly spreading the disease. Making large populations of mosquitoes unable to host Plasmodium falciparu by progeny would be an important step towards the eradication of the dangerous infection.
Anthony A. James, Professor at the University of California Irvine, along with his team, were responsible for coming up with a technique in which they splice in a gene, helping the mosquitoes develop antibodies against malaria. The mentioned Crispr method let him create the equivalent of a dotted outline in the genome of a mosquito, which would later be cut out by molecular scissors. The mosquito’s genome needs to be cut in the right places so the newly inserted gene can be produced normally without affecting other factors.
Genetically modifying each mosquito larvae would be a Herculean task, especially if the goal is eradicating malaria on a global scale. That’s why Valentino Gantz and Ethan Bier, from University of California San Diego, tried to find a way for mosquitoes to pass the malaria-blocking gene into their offspring, which would alter a whole population of the insects way faster. To accomplish this, they manipulated the gene drive, which is a DNA sequence that female chromosomes can copy from males, making the malaria resistance hereditary.
“This opens up the real promise that this technique can be adapted for eliminating malaria,” James said.
However, researchers warn that there’s a genetic block to the gene drive present on female mosquitoes, which could hinder the hereditary process of the malaria-blocking gene. They will keep experimenting to test if their method can be safe and effective to combat the disease.