While Covid-19 As a pandemic rages around the world in 2020, another disease is quietly infecting more than 220 million people on the African continent: malaria. That year, the illness led to more than 600,000 people died, most of them are children. Caused by a parasite Plasmodium, disease spread through the bite of an infected woman Anopheles mosquito.
Insecticide-treated bed sheets and indoor spraying have long been among the most effective strategies to combat the disease. But decades of use of these chemicals have reduced their effectiveness.
It happens like this: The insecticide kills most of the mosquitoes in an area. But a small number can survive because something about their genetic makeup makes them unaffected by pesticides. The mosquitoes in that small population mate with each other and pass their genes on to their offspring, creating mosquitoes that are more resistant. In some cases, resistance developed just a few years after insecticide use. It makes fighting deadly mosquitoes a constant game of a mole.
Insecticides remain the front line in combating malaria, because interventions such as building mosquito-proof house is still in testing, and the effort to develop a vaccine has taken decades. Last summer, the World Health Organization recommended Mosquirix, The first anti-parasitic vaccineintended for African children under the age of 5, but it is only 30% effective at preventing critical illness and will take years to gain acceptance and distribution among countries.
Researchers at UC San Diego and the Tata Institute of Genetics and Society in India have developed a potential way to combat it: Using Crispr gene editing, they replaced an insecticide resistance gene in fruit flies with normal gene form and propagate this change. through insects in the laboratory. The approach, known as gene drive, is described in January 12 paper in Nature Communicationsand the team believes it can be converted into mosquitoes.
“This technology I think will provide a solution to the conundrum we’re facing right now, which is not yet having a drug,” said Ethan Bier, professor of cell and developmental biology at UC San. Any new insecticide developed over the past 30 years. Diego and the paper’s senior author. “If you can keep using the things you already have by re-irritating the mosquitoes with those things, I think that would be a huge benefit.”
Gene drive is a type of technology that bypasses the laws of heredity to spread a trait in a population faster than it would naturally occur, forcing the gene to become the offspring of the population. In this case, the change essentially resets the gene pool to what it was before the insect developed resistance to a particular pesticide.
The team’s gene drive uses a molecule called RNA that instructs the Crispr system to remove the unwanted variant of the gene — in this case, the pesticide resistance mutation called kdr. When one parent passes on its genetic information to their children, a protein called Cas9 binds to the guide RNA, cuts out the mutated gene and replaces it with the normal variant from the other parent. again. Then the normal variant is copied and all offspring inherit it.
