Malaria is a mosquito-borne disease that causes fever, chills, and flu-like illness; if left untreated, it may even lead to death. The fight against malaria has been successful in the early 2000s, with 1.5 billion cases and 7.6 million deaths averted since 2000, but progress has been plateauing in the last five years. A report shows that in 2019, there were an estimated 229 million cases of malaria occurring worldwide and 409,000 deaths. One reason for this recent lack in progress is due to the rise in insecticide resistance in mosquitoes. Therefore, in order to curb malaria, new tools are needed to eradicate it, such as a technology called gene drive.
Briefly, gene drive is a genetic engineering technique that causes a particular gene to be passed on hereditarily at a higher than normal rate. For example, most genes have a 50% chance of being passed from parent to offspring based on the laws of heredity. However, a gene drive can disrupt this law —the gene can be transferred to more than 50% of the offspring, causing it to dominate the entire population. Therefore, synthetic gene drive can be used to spread an antimalarial trait throughout a mosquito population at a relatively fast pace, thereby eliminating malaria. However, there have been many problems with using this technology for malaria specifically; many synthetic gene drives developed would either (1) modify an important part of the genome that leads to poor survivability of the organism, thus disrupting the population dynamics, or (2) affect a less important part of the genome that leads to poor preservation of the gene drive, reducing its ability to be passed onto offspring.
Recently, a group of scientists from Imperial College London developed an approach that targets the introns of the mosquito genome. Introns are a part of the DNA that do not later on get translated into proteins; in other words, they are silent and do not affect the function of the DNA. Thus, this new synthetic gene drive is able to target an important part of the genome without worsening the survivability of the organism, thus solving the previous problem of affecting the population dynamics. Indeed, the researchers tested the gene drive in the African malaria mosquito A. gambiae and found that mosquitoes that carry the gene drive were able to pass on the genes to their offspring while remaining as healthy as mosquitoes that do not carry the gene drive. Therefore, their experiments provide preliminary yet promising evidence that their new approach of synthetic gene drives could work in mosquitoes. Hopefully, in the near future, synthetic gene drive can help us spread antimalarial properties to all mosquitoes that spread malaria, eliminating malaria once and for all.
The first author of the study, Astrid Hoermann, is a research associate in the Department of Life Sciences in Imperial College London, UK.
Managing Correspondent: Wei Li
Press Article: Editing a Mosquito’s Gut Genes To Make Them Spread Antimalarial Genes, Technology Networks.