Genetically engineered mosquitos stop malaria in its tracks

Students doing research in Anthony James’ basement insectary at the University of California,

Irvine, defied the laws of evolution, to create mosquitoes that carry a gene which stops the

malaria parasite from growing.

Malaria is caused when a mosquito bite transmits the single-celled parasite plasmodium. Though

treatable, 670,000 people die annually from the disease, the majority of them young children in

sub-Saharan Africa.

After decades of what James, a specialist in mosquito biology, says was mostly obscure work

done by a few insect specialist focused on constructing a genetic solution to malaria, positive

results were reported by him and half dozen colleagues on Nov. 23, in the Proceedings of the

National Academy of Sciences. The scientists explained that the results were achieved using

technology called a "gene drive," which was built with gene-editing technology known as

CRISPR.

The bugs in question had fathers with fluorescent red eyes and their mothers normal ones, and by

extension, their eyes should have been half red. Instead, 99% had glowing eyes, another

indication that these were not your ordinary mosquitoes.

The super bugs have two important genetic additions—genes that manufacture antibodies

whenever a female mosquito has a ‘blood meal’, binding to the parasite's surface, and stopping

its development. Usually only half of these mosquitoes’ offspring would have these new genes

and increasing that percentage is where the CRISPR shines.

Components of the CRISPR system are added to a gene drive so that normal genes are edited,

with the genetic cargo included. In James’ lab, nearly all the mosquitoes had the genetic addition.

For over a decade, a functioning gene drive in mosquitoes has been anticipated by public health

organizations, as a revolutionary way to combat malaria. Now that it has come to fruition, there

is the question of whether this technology is safe enough to be released into the wild.

Should these evolutionary marvels be exposed to mosquito populations, their "selfish" genetic

cargo would spread to their counterparts, potentially stopping the transmission of malaria.

In 2014, Gene drive researcher at Harvard University’s Wyss Institute, Kevin Esvelt, along with

other scientists warned that gene drives were on the brink of becoming reality (see "Protect

Society from Our Inventions, Says Genome Editing Scientists") and required the attention of

regulators and the public. He is concerned that the California researchers’ safety regulations are

not up to scratch and wants them to install a genetic "reversal drive" so the change can be

undone, if necessary. According to him, “An accidental release would be a disaster with

potentially devastating consequences for public trust in science and especially gene-drive

interventions.” 

However, James says the experiment was completely safe, as the mosquitoes were kept behind a

series of locked, card-entry doors. He added that as they are not native to California, should any

escape, they wouldn't be able reproduce.

The National Academy of Sciences plans to release recommendations in 2016, on "responsible

conduct" required by scientists and companies using this technology.

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