Hey there! I do actually have a degree in Ecology and Evolutionary Biology. Something that gets drummed into you in that field: Nature is extremely unpredictable and when we mess around with it we make it worse as often as we help.
And I did read the article, as well as several other pieces on the topic. I work in invertebrate conservation so I’ve been following this story for a while. I’m well aware that they are only currently planning to target Anopheles gambiae.
While the goal is to crash mosquito populations near malaria-ridden villages, there is a not insignificant chance that once it’s out in nature this gene-drive could drive An. gambiae extinct. Once these genes are out in the world they can self-perpetuate and there’s no putting them back in the box if they start having effects we don’t like. And the people behind this study seem relatively unconcerned with the possible extinction of An. gambiae.
There is one line in the linked article mentioning the possibility of replacing the wiped out mosquitoes with other members of their species that have been modified to not carry malaria, but I haven’t seen that option mentioned in some of the recent, more in-depth articles on the subject. It seems that pursuing that option has been put on the back-burner or scrapped altogether, which is a shame because that would make this situation far less concerning.
A couple of reasons why we should be nervous about this:
1) There is already talk of using this technique on the mosquitoes that carry dengue and Zika (Ae. aegypti and Ae. albopictus) if this is successful. And seventy mosquito species are capable of transmitting malaria (and An. gambiae itself is actually a complex of eight closely related species); are we going to wipe them all out eventually? Seventy whole species?
While using CRISPR to eliminate vectors of diseases that cause human pain and suffering is a noble cause, how long do you think it will be before this technology is being utilized for far less worthy purposes? How long before we use CRISPR as a first resort to eliminate new vector-borne diseases instead of a last resort? How long until we are using it to eliminate distasteful animals that are merely agricultural or household pests rather than disease vectors?
2) We are currently in the middle of a mass extinction event, part of which includes a terrifying decrease in insect numbers that some scientists fear may herald ecological collapse. With this backdrop, a possible trend of intentionally driving insect species extinct or crashing their population numbers is particularly disturbing.
Not to mention we are potentially wiping out a species that took millions of years to evolve, that is just as complex and unique as polar bears or whooping cranes or elephants. If the extinction of a more charismatic species were on the table, even if it were causing thousands of human deaths, don’t you think we would be more eager to find an alternate solution? Don’t you think there would be a greater priority placed on avoiding the complete extinction of An.gambiae or reintroducing malaria-free An. gambiae after wiping out the diseased ones?
The extinction of any species destabilizes an ecosystem. It also leaves a niche open, which could be replaced with something worse or something we don’t have experience dealing with.
3) It is disingenuous to say there will not be negative ecological consequences. There will almost certainly be some negative ecological consequences, though they might not be terrible or immediately obvious.
Remember mosquitoes are pollinators. Their aquatic larvae are an important food source for fish and amphibian larva and adult mosquitoes serve as prey for dragonflies, spiders, bats, and other animals. Even a study associated with Target Malaria itself has stated that when one mosquito species is eliminated or reduced the type and relative abundance of other mosquito species present in the area will likely also change.
We are basically taking a calculated risk that the positives will outweigh the negatives. We can say that seriously negative fallout is unlikely, but we absolutely cannot guarantee that there won’t be some unforeseen negative consequences.
Malaria kills around 445,000 people a year, and that is a heck of an argument for why this is worth trying. But we need to honestly discuss the fact that there are risks and that there will likely be at least some unforeseen ecological consequences even if the decrease in malaria deaths is worth it.
I do admire the diligence that Target Malaria has had in examining the possible ecological consequences of their work. I also admire their efforts to work with African communities on this matter, although there are still some African activists who are highly uncomfortable with an American/European-run group setting loose an untested and controversial new technology on African soil.
Even if we decide that this is worth trying, it should still be something that makes us nervous and wary. And this technology absolutely should remain highly controversial, because we should never get comfortable doing this kind of thing often or without serious forethought. This is a slippery slope that we need to be really careful about.
TLDR: This technology may be worth it to reduce human death from malaria, but we should still remain highly wary of intentionally crashing the numbers of/wiping out a species without exploring other options first. And we should be honest that there is a definite possibility of unintended negative consequences (even if we think they are unlikely or are worth the risk) because nature is notoriously complicated and unpredictable.
