As It Happens

Researchers modify mosquitoes' genes, making them unable to see humans

In California, biologists have found a way to mutate a mosquito's vision by taking out the light receptors in the insect's eyes. Professor Craig Montell hopes this research may someday help eliminate the Aedes aegypti mosquitoes.

Biologists' discovery could be the first step to eliminating the invasive species from non-native habitats

A female Aedes aegypti mosquito is seen sucking blood from a human host in this 2006 photograph. (Frank Hadley Collins/Centers for Disease Control and Prevention)

It may sound like a superpower, but a new study is looking at ways for people to be invisible to mosquitoes. 

But it doesn't come in a spray can of bug repellant. Instead, it requires editing the genes of the mosquito itself. In California, biologists have found a way to mutate a mosquito's vision.

Craig Montell is a professor in the molecular, cellular and biology department at University of California Santa Barbara and co-author of the study, which was published last month in the journal Current Biology.

His team was able to use gene-editing CRISPR technology to mutate the light receptors in the mosquito's eyes. 

The mosquitoes they worked on have five light receptors in their eyes, which are known as opsins. After biologists successfully removed two of those receptors, the mosquitoes lost their ability to visually identify humans — although they weren't blind. 

"If you eliminate both opsins, their ability to find their targets is reduced. It's just not eliminated," Montell told As It Happens host Helen Mann. "They still can behave in a way that shows that they still have a visual capacity."

The research focuses on a type of mosquito known as Aedes aegypti, which is native to Africa and spreads diseases like dengue, Zika, and yellow fever. 

"The Aedes aegypti mosquitoes are spreading, because they're invasive, with global warming and worldwide travel," Montell said.

"They are coming to new places. And you can't even be sure that Canada is not going to have a problem with Aedes aegypti."

The Aedes aegypti mosquito is known to carry deadly diseases. (Evans Caglage/The Associated Press)

This type of mosquito was first reported to have appeared in Canada in 2017 in southern Ontario. Since then, colonies have been found in other places across the country.

Montell says because this bug is an invasive species, getting rid of them won't hurt the ecosystem. 

"What you're doing is you're restoring the environment to what it was," he said.

He added that the mosquitoes would struggle to live and procreate with reduced vision. 

Montell's team doesn't do field research, but he said this is just the first step in understanding how mosquitoes find us. It won't eliminate the insect now, but this research could be used by people looking for solutions to get rid of it. 

"The immediate next steps in our research is we're also trying to understand more about the mechanisms that mosquitoes use to employ other human cues," Montell said. 

"The next things that we're currently doing in the lab is really studying the kind of receptors that mosquitoes use to find people through other senses."

Written by Philip Drost. Interview with Craign Montell produced by Kate Cornick.

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