GM mosquitoes to help block malaria

Scientists have created a strain of mosquitoes capable of rapidly introducing malaria-blocking genes into a mosquito population through its progeny, ultimately eliminating the insects’ ability to transmit the disease to humans.

Using a groundbreaking gene editing technique, researchers inserted a DNA element into the germ line of Anopheles stephensi mosquitoes that resulted in the gene preventing malaria transmission being passed on to 99.5 per cent of offspring. A stephensi is a leading malaria vector in Asia.

“This opens up the real promise that this technique can be adapted for eliminating malaria,” said Anthony James, professor at the University of California, San Diego.

The study underlines the growing utility of the CRISPR method, a powerful gene editing tool that allows access to a cell’s nucleus to snip DNA to either replace mutated genes or insert new ones.

Researchers packaged anti-malaria genes with a Cas9 enzyme (which can cut DNA) and a guide RNA to create a genetic “cassette” that, when injected into a mosquito embryo, targeted a highly specific spot on the germ line DNA to insert the anti-malaria antibody genes.

To ensure that the element carrying the malaria-blocking antibodies had reached the desired DNA site, the researchers included in the cassette a protein that gave the progeny red fluorescence in the eyes.

As many as 99.5 per cent of offspring exhibited this trait, which James said is an amazing result for such a system that can change inheritable traits.