Of the 625,000 people who will die from malaria each year, the majority will be children under the age of 5 living in Sub-Saharan Africa. Though some scientists have been working tirelessly on vaccines and updated treatment options, others have been focusing on targeting the vector that transmits the parasite: mosquitoes.
A new study, published in the Proceedings of the National Academy of Sciences, describes the ability to use an exciting form of genetic engineering in order to create a new kind of mosquito that is able to resist the parasite and thus, prevent the spread to humans.
"This opens up the real promise that this technique can be adapted for eliminating malaria," senior author Anthony James explained in a press statement.
The easiest way to understand the technique is to think of the traditional Punnett square that everyone uses when learning basic genetics. As each parent passes one copy of a gene variant down to its offspring, it will exist in about half of them. However, this new technique boosts the ability to be passed along, making nearly certain that all will have the variant. In this case, researchers created a sequence of DNA that signals the creation of antibodies that attack the parasite anytime it eats, prohibiting the spread.
To ensure that the gene variant doesn't die out, the scientists have also created what is known as a gene drive. Researchers have utilized the relationship of a DNA repair enzyme called Cas9 and clustered regularly interspaced short palindromic repeats (CRISPR) to target specific DNA sequences. Though this occurs naturally to stop viral DNA from integrating with the host genome, scientists have been able to manipulate the process and use it to insert modified genetic sequences exactly where they want them to go. In this case, the researchers are using it to ensure that the gene variant that resists the parasite that causes antibody creation to get passed along.
To verify if the genes were inserted correctly, the scientists also included a gene variant that causes brilliant red eyes. They found that more than 99 percent of the mosquitoes used for this line of experimentation had the fluorescence in the eyes they were hoping to see.
If these engineered mosquitos were released to breed with mozzies in the wild, this genetic variant would spread incredibly quickly. In a matter of a few generations (which wouldn't take long, given that they complete their life cycle in under two weeks), the majority of that population would be unable to pass along the parasite that causes malaria. The implications are obviously huge.
However, there are still some — ahem — bugs to be worked out with these engineered mosquitoes. In subsequent generations, females had difficulty passing the mutation along to their offspring. The ongoing research is addressing this problem.
"This is a significant first step," James continued. "We know the gene works. The mosquitoes we created are not the final brand, but we know this technology allows us to efficiently create large populations."
The problem, it seems, is not a matter of whether scientists can do it, but if they should.
As MIT Technology Review points out, there could be catastrophic consequences if these transgenic insects were able to escape accidentally. Even if there was nothing to fear with the gene drive, science illiteracy among the general public could cause overwhelming fear and misunderstanding about what the genetic engineering is actually capable of achieving.
It's understandable to take the public's reaction into consideration, as 60 percent of Americans believe genetically modified food is unsafe, despite overwhelming amounts of research that show GMO foods are perfectly safe. Despite the tangible benefit these transgenic mosquitoes could provide, fear has historically gotten the better of people. Rather than blindly stifling progress due to ignorance and fear, it's imperative to improve scientific literacy among the public and elected leaders who vote on scientific funding.
As of right now, it's unclear what the fate of this program will be. There are still plenty of discussions needed to debate the risks and benefits of using gene drives in this way. While the researchers are optimistic that their genetically engineered mosquitoes will be used to reduce malaria at some point, there is still much work to be done and it's all very encouraging.