Scientists engineer mosquito with malaria-blocking genes

Scientists aiming to take the bite out of malaria have produced a strain of mosquitoes carrying genes that block its transmission, with the idea that they could breed with other members of their species in the wild and produce offspring that cannot spread the disease. The goal is to release genetically modified mosquitoes to mate with wild mosquitoes so that their malaria-blocking genes enter the gene pool and eventually overrun the population, short-circuiting the species’ ability to infect people with the parasites.

James engineered immune system genes that could spur a mosquito’s body to develop antibodies to attack the parasite, so that it couldn’t transmit the infection.

“This work suggests that we’re a hop, skip and jump away from actual gene drive candidates for eventual release” in nature, he said.

With further development the team of scientists at the University of California believe they will be able to establish an anti-malarial mosquito population, that could help eradicate the disease, which sickens millions across the world each year. This tool allows access to a cell’s nucleus to remove DNA and insert new or mutated genes. Results appear this week in the early online edition of Proceedings of the National Academy of Sciences.

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.

They also cautioned that scientists working in this field must “interact openly and freely with the potential end users“.

This trait, though, could only be inherited by about half of the offspring.

“It can spread through a population with great efficiency, increasing from 1 percent to more than 99 percent in 10 generations, or about one season for mosquitoes”, said University of California-San Diego biologist Valentino Gantz.

The two groups collaborated to fuse Professor Bier and DrGantz’s method with Professor James’s mosquitoes.

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

The researchers said they had achieved a rate of transmission of 99.5 percent.

“This is the kind of technology where the first trial has to be a success”, he said. “The mosquitoes we created are not the final brand, but we know this technology allows us to efficiently create large populations”.

Malaria is one of the world’s leading health problems. Although the disease is curable and preventable, it claims a large number of lives.

Nijole Jasinskiene, Olga Tatarenkova, Aniko Fazekas and Vanessa Macias of UCI contributed to the study, which was supported by grants from the National Institutes of Health (AI070654, NS029870, AI29746 and AI116433) and the W.M. Keck Foundation and a gift from Drs.