Bioethics Blogs

Gene Drive Research Takes Aim at Malaria

Malaria has afflicted humans for millennia. Even today, the mosquito-borne, parasitic disease claims more than a half-million lives annually [1]. Now, in a study that has raised both hope and concern, researchers have taken aim at this ancient scourge by using one of modern science’s most powerful new technologies—the CRISPR/cas9 gene-editing tool—to turn mosquitoes from dangerous malaria vectors into allies against infection [2].

The secret behind this new strategy is the “gene drive,” which involves engineering an organism’s genome in a way that intentionally spreads, or drives, a trait through its population much faster than is possible by normal Mendelian inheritance. The concept of gene drive has been around since the late 1960s [3]; but until the recent arrival of highly precise gene editing tools like CRISPR/cas9, the approach was largely theoretical. In the new work, researchers inserted into a precise location in the mosquito chromosome, a recombinant DNA segment designed to block transmission of malaria parasites. Importantly, this segment also contained a gene drive designed to ensure the trait was inherited with extreme efficiency. And efficient it was! When the gene-drive engineered mosquitoes were mated with normal mosquitoes in the lab, they passed on the malaria-blocking trait to 99.5 percent of their offspring (as opposed to 50 percent for Mendelian inheritance).

This inheritance pattern persisted through three generations of gene-drive engineered male mosquitoes mated with normal females. With such highly efficient transmission, the researchers estimate that the malaria-blocking trait could be spread throughout an entire local population of mosquitoes in just a single breeding season by releasing one gene-drive engineered mosquito for every 100 mosquitoes in the wild.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.