WASHINGTON • Scientists aiming to take the bite out of malaria have produced a strain of mosquitoes carrying genes that block its transmission, with the idea they could breed with other members of their species and produce offspring that cannot spread the disease.
The researchers said on Monday that they used gene-editing, a genetic engineering technique in which DNA can be inserted, replaced or deleted from a genome, on a species called Anopheles stephensi that spreads malaria in urban India.
They inserted DNA into the germ line - cells that pass on genes from generation to generation - of the species, creating mosquitoes with genes that prevent malaria transmission by producing malaria-blocking antibodies that are passed on to 99.5 per cent of offspring.
Malaria is caused by parasites transmitted to people through the bites of infected female mosquitoes. Scientists' 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.
"It can spread through a population with great efficiency, increasing from 1 per cent to more than 99 per cent in 10 generations, or about one season for mosquitoes," University of California-San Diego biologist Valentino Gantz said.
University of California-Irvine molecular biologist Anthony James said: "We do not propose that this strategy alone will eradicate malaria." But in conjunction with treatment and preventive drugs, future vaccines, mosquito-blocking bed nets and eradication of breeding sites, it could play a major role in sustaining the elimination of malaria, he added.
The research was published in the Proceedings of the National Academy of Sciences.