Scientists breed mosquitoes with 'malaria-blocking genes'

This photo provided by the Centers for Disease Control and Prevention (CDC) shows a feeding female Anopheles stephensi mosquito crouching forward and downward on her forelegs on a human skin surface, in the process of obtaining its blood meal through its sharp, needle-like labrum, which it had inserted into its human host. (James Gathany/ CDC / via AP)

Scientists have created mosquitoes with "malaria-blocking genes" which can be passed onto their offspring, the University of California announced on Monday.

Researchers at the university's Irvine, Calif., and San Diego campuses teamed up to develop a method of inserting anti-malaria genes into the DNA of Anopheles stephensi mosquitoes.

According to a university press release, the mosquito then has an "astonishing" 99.5 per cent chance of passing the gene down to its offspring.

That means, in time, the discovery could help eliminate a disease that kills approximately half a million people each year.

"This opens up the real promise that this technique can be adapted for eliminating malaria," Anthony James, a molecular biology, biochemistry, microbiology and molecular genetics professor said in the release.

The mosquitoes' creation follows a series of earlier developments in gene mutations, insects, and diseases.

James has previously researched ways to introduce anti-dengue fever antibodies to mosquitoes, but the trait could only be inherited half of the time.

Then, earlier this year, University of California biologists Ethan Bier and Valentino Gantz developed a new method for modifying genetics in fruit flies. Using this technique, mutations could be inherited 95 per cent of the time.

Scientists fused James', Bier's and Gantz' findings to create mosquitoes that are both malaria resistant and capable of passing that trait down to the majority of their offspring.

To test their method, researchers inserted a protein that gave the offspring red eyes alongside the malaria-blocking antibodies. This way, they could easily see which mosquitoes inherited the traits.

In the end, they found that the red eyes and anti-malaria genes were passed down to 99.5 per cent of the offspring.

According to the Centers for Disease Control and Prevention, malaria sickens approximately 200 million people a year and kills nearly half a million annually.

The centre says about 3.4 billion people live in areas where they are at risk of contracting the disease, but children, babies, and pregnant women – mostly in Africa – are the most likely to die from it.

Scientists now hope to introduce a malaria-resistant insect into mosquito populations in the wild, where it can breed and pass on the anti-malaria genes, and potentially help eliminate the disease.

But first, James said, further research and possible field studies are necessary.

"We know the gene works. The mosquitoes are not the final brand, but we know this technology allows us to efficiently create large populations," James said. "This is a significant step."