Researchers used a gene editing tool, CRISPR, to wipe out a population of malaria-carrying mosquitoes in the lab
Questions remain about how releasing this technology into the wild would impact the environment
Researchers have rendered a population of mosquitoes in a lab sterile using the gene-editing tool CRISPR-Cas9 by homing in on a specific target in insect DNA – the doublesex gene – raising the possibility of eradicating disease-carrying species of the insect entirely, according to a new study published Monday in Nature Biotechnology.
In the study, scientists at Imperial College London used the technology to wipe out a population of caged mosquitoes that are able to transmit malaria, targeting a genetic sequence that leads to male and female traits. After a number of generations, they found that 100% of these mosquitoes were affected.
“The difference in the gene content between male and female is very, very minimal” in mosquitoes and humans alike, said study author Andrea Crisanti, professor of molecular parasitology and microbiology at Imperial College London.
Doublesex, as the name implies, controls how mosquitoes differentiate into male and female. Females with two copies of the mutated gene didn’t develop properly and couldn’t reproduce, while males developed normally and continued spreading the mutation. Mutant females also failed to develop the long, needly proboscis they need to bite humans and suck blood.
What’s more, the experiment seemed to succeed where others have failed – the spread of these mutant genes was not thwarted by the mosquitoes developing resistance.
“We have selected a target site that cannot be mutated or changed by the mosquito without paying a high price,” Crisanti said.
The researchers note this doesn’t necessarily prove their methods are “resistance proof.” Experts say this could play out very differently outside small, confined spaces and among many other species of mosquitoes – only some of which carry the parasite that causes malaria.
But even when it comes to suppressing or extinguishing a species of mosquito, are we opening Pandora’s Box and releasing something into the world we don’t fully understand? Or will the only major impact be a positive one for humans while other organisms – less harmful ones, ideally – take these bugs’ place in the ecosystem?
“That’s an open question,” said Catherine Hill, professor in the department of entomology at Purdue University. “We’re very interested in protecting human health, but at the same time protecting the environment.”
Hill said we’re still untangling how mosquito