How gene drive works

A scientist sits at a desk and looks into a microscope

Currently, we are evaluating a number of approaches to reduce the number of malaria mosquitoes using genetic modification, in particular gene drive technologies.

This work is still at an early stage, but our models indicate that this method has the potential to significantly reduce the numbers of malaria mosquitoes, and the transmission of malaria, within a socially relevant timeframe.

“Gene drive is a genetic phenomenon that occurs in nature and causes a selected trait to spread rapidly through a species via sexual reproduction over several generations. Gene drive works by increasing the likelihood that a modified gene will be inherited by its offspring. Normally, genes have a 50/50 chance of being inherited, but gene drive systems could increase that chance to upwards of 99 percent. This means that over the course of several generations, a selected trait could become in-creasingly common within a specific species.”

Professor Austin Burt

The goal of all of the gene drive approaches we are investigating is to produce genetically modified  Anopheles gambiae  mosquitoes that can pass a genetic modification on to a high percentage of their offspring, so the modification is established throughout the specific population relatively quickly and is effectively “self-sustaining”. The objective of the genetic modifications we are making is to reduce the number of female  Anopheles gambiae  mosquitoes because they are the ones who transmit malaria when they bite humans.

To do so, we are introducing genes that produce enzymes (called nucleases) into Anopheles gambiae. These enzymes recognise and cut very specific sequences of DNA. In Target Malaria’s case, our researchers precisely cut and therefore disrupt the specific gene sequences of interest , such as fertility genes or sex determination genes that will impact reproduction and thus population size. This makes the reduction of the malaria mosquito population relatively cost-effective and sustainable to implement because the mosquitoes themselves do the work.

Two of the main areas we are currently focusing on are reducing female fertility and biasing the sex ratio of mosquito populations. So far, the approach targeting female fertility is our most promising.