Of all the things I thought would help fight malaria, 100-year-old mosquitoes would not have been high on the list. Then I learned about the work of Dr. Mara Lawniczak.
An evolutionary geneticist at the Wellcome Sanger Institute in the United Kingdom, Mara has spent much of her career trying to understand how the genomes of various mosquito species have changed in response to humans’ attempts to kill them. When, where, and how fast has it happened? What does that say about how they might evolve in the future?
In recent years, genetics has become an increasingly important tool for fighting malaria. Because mosquitoes breed so fast (a female can lay thousands of eggs in her lifespan of a couple of weeks), they evolve rapidly, at least compared to humans. By studying their genes, researchers are able to understand things like how they develop resistance to insecticides, crucial information that helps humans stay one step ahead.
After a few years of studying mosquitoes’ genomes, Mara had grown frustrated by the fact that the only insects available for study were ones that had been captured recently. Without DNA from their ancestors, there was no way to know how their genomes had responded to decades of human attacks. “We were often saying, ‘If only we could look into the past,’” Mara says. “And then it suddenly struck me: I'm sure there are historical collections of mosquitoes around.”
She was right. The Natural History Museum in London has a collection of 34 million insects from all over the world, carefully collected and preserved. Among the collection is a large sample of mosquitoes dating from 1936, when a British entomologist named H.S. Leeson spent a year in East Africa capturing and cataloguing the insects in the hope of learning more about malaria. Leeson didn’t know it at the time—DNA wouldn’t be discovered until the 1950s—but his collection of mosquitoes would become a vast source of genetic material that someone like Mara could study.
Mara reached out to the museum’s curators. They wanted to help, but there was a problem: Extracting DNA from the insects would require Mara to grind them up. Since the museum’s mission is to preserve its collection for future generations, they couldn’t let her do that.
So Mara and her colleagues invented a way around the problem. Working with the museum’s team, they developed a novel way to extract DNA from mosquitoes without damaging the specimen.
They affectionately call this work Project Neandersquito. It’s not because the mosquitoes date from the time of Neanderthals, some 40,000 years ago—this isn’t Jurassic Park, where they extract dinosaur DNA from a prehistoric mosquito trapped in amber. It’s because the mosquitoes they’re studying are 1,000 or 2,000 generations removed from modern ones, just as Neanderthals are more than 1,000 generations removed from modern humans.
Mara’s team has made some surprising finds. For example, because mosquitoes started developing resistance to the insecticide DDT in the 1950s, they expected to see genetic mutations for resistance appearing around the same time. But they didn’t. “We still don't see them even as late as the 1980s,” she says. “So the mosquitoes were somehow making themselves resistant to DDT in ways that we still don't really understand.”
They also hope to get insight into what's coming. “How fast can mosquitoes evolve? And as we throw new control initiatives at them, how quickly are they going to get around them?” Other labs are now using the process devised by the Lawniczak Group to do their own research.
Project Neandersquito is just one of the ways Mara and her team are using genomics to advance the fight against malaria. A different project, the Malaria Cell Atlas, is providing new genetic data that could inform the effort to make better malaria drugs and vaccines. Another project is designed to make it easier and cheaper to identify a mosquito’s species using its DNA—it’s surprisingly hard to do just by looking—as well as whether it’s carrying the parasite that causes malaria, and even which species of the parasite it has. Ultimately, the project’s goal is to help governments get data that will help them get the most out of their anti-malaria efforts.
Mara would be the first to say that these are just a few examples of the tools the world needs to eradicate malaria. It’s going to take global cooperation from governments, the private sector, and academia. And now we can add natural history museums to the list.