Graphic by Callie Wohlgemuth ’21
BY VIVIAN LIVESAY ’21
A team of biologists at the Imperial College London have created genetically engineered mosquitoes that they believe could eliminate malaria by targeting a disease-carrying mosquito species, specifically Anopheles gambiae, which is native to sub-Saharan Africa.
Gene-drive, the technology that allows scientists to manipulate genes, works by targeting the stretch of DNA responsible for sex determination, which causes sterility in female mosquitoes. This leaves males unaffected and able to propagate the mutant gene. In laboratory conditions, this caused the population of mosquitoes to crash within 11 generations, according to a report published in Nature.
Eliminating malaria would have huge implications for populations in sub-Saharan Africa. “Its eradication could save tens of thousands of lives, mostly children under 5,” said Girma Kebbede, a professor of geography at Mount Holyoke who specializes in economic development. “It could also reduce costs to individuals and health care systems and increase labor productivity, household incomes and life expectancy,” said Kebbede.
According to UNICEF, there are 300- 600 million cases of malaria every year, which results in a child dying of malaria every thirty seconds. With malaria-carrying mosquitoes eliminated, more children would be able to live healthy lives and get an education, which would benefit African economies by freeing up resources that are spent controlling and treating malaria.
Despite the potential benefits, there are serious concerns about the consequences of driving such a common species to extinction. Mosquitoes are prey for many species of birds, bats and frogs, which in turn support other parts of the food chain. Studies have not yet been conducted to see how severely the genetically modified mosquitoes would impact the ecosystems where they live. Dr. Kevin Esvelt, one of the authors of the study, addressed this in the New York Times. “The known harm of malaria greatly outweighs every possible ecological side-effect that has been posited to date, even if all of them occurred at once,” said Esvelt.
Catherine Levecque ’19, a biology major and mentor in ecology, also spoke about these concerns. “Most biologists agree that mosquitoes are not entirely essential to the food chain, and that the benefits of eradicating them outweigh the negatives,” said Levecque. “That being said, predictions about ecological impact are based on mathematical models and our current scientific understanding, and that’s never a sure thing.”
Understanding possible consequences is essential before the gene-drive is released into the wild. Due to the nature of a gene-drive, there is no way to restrict the impacted population of mosquitoes to a single country. Moreover, researchers have acknowledged that the gene-drive has the potential to spread between other mosquito species, which occur on every continent except Antarctica. Mosquitoes can easily stow away on airplanes and cargo ships, meaning that males carrying the gene-drive could possibly interact with populations of mosquitoes around the world.
Levecque also voiced concerns that the efforts put toward combatting malaria may be misplaced. “It is concerning to me that malaria research is targeting mosquitoes rather than targeting the disease itself,” Levecque said. “It seems to me that prioritizing malaria vaccine developmentwould be a more effective public health effort.”
While concerns range from ecological impact to allocation of resources arise surrounding genetically modified mosquitoes, eliminating or reducing the mosquito population has the potential to save millions of lives and to bolster the economies of many struggling nations.