Tuesday, September 25, 2018

Giving Malaria a Deadline

Malaria is among the world’s worst scourges. In 2016 the disease, which is caused by a parasite and transmitted by mosquitoes, infected 194 million people in Africa and caused 445,000 deaths.

But biologists now have developed a way of manipulating mosquito genetics that forces whole populations of the insect to self-destruct. The technique has proved so successful in laboratory tests that its authors envisage malaria could be eliminated from large regions of Africa within two decades.

A team led by Andrea Crisanti, a biologist at Imperial College, London, altered a gene that disrupts the mosquito’s sexual development; the females become infertile but the males remain able to spread the debilitating gene to an ever-dwindling number of progeny. Dr. Crisanti found that laboratory populations of mosquitoes can be driven to extinction within 11 generations, he and colleagues report in Monday’s issue of Nature Biotechnology. Wild populations could be made to crash in about four years, according to computer models.

The technique involves equipping mosquitoes with a gene drive, a genetic mechanism that forces a gene of choice into all of an organism’s offspring. (Normally, sexual reproduction would pass the gene to only half the progeny.) Genes carried by a gene drive therefore can spread very rapidly through a population, which makes the technique both powerful and potentially dangerous. No gene drive has yet been released in the wild. (...)

Launching a gene drive into the wild is risky. Once released, it can’t be recalled or easily disabled should anything go awry. In 2016, the National Academy of Sciences called for extensive tests and public consultationbefore any gene drive is released.

The theory of how gene drives could be used to control pest populations was laid out in 2003, in an article by Austin Burt, a biologist at Imperial College, London, and a co-author on the new paper. He hopes that a small-scale field trial can be started in Africa in five years.

by Nicholas Wade, NY Times | Read more:
Image: Dr. Tony Brain/Science Source
[ed. Bad idea, and not just because of mission creep. See also: The Law of Unintended Consequences (of which, biological intervention has had more than its fair share of historical failure). As Ian Malcolm would say "life finds a way".]