Wednesday, July 21, 2010

Malaria-proof Mosquitoes!

This is seriously cool. Entomologists and geneticists at the University of Arizona modified a single gene in the Anopheles stephensi mosquito in the hope of shortening its lifespan to the point where the malaria parasite would be unable to mature fully before the host died. Instead, they entirely blocked infection by Plasmodium falciparum, the primary human malaria parasite. They still don't understand entirely why it worked (you can find the actual published data here), but by all accounts it sure seems to.

Malaria is one of those diseases that kills a million or so people each year, but because nearly all of those million people live in third-world countries not much gets done about it. Drug companies can't make much profit from making a drug that only poor people would buy, so progress has been slow. In fact, most of the current efforts to fight malaria revolve around mosquito control rather than targeting the parasite. There's some really cool research going on here at the University of Florida that revolves around designing pesticides that target the mosquitoes' uniquely alkaline digestive system, theoretically leaving other insects, fish and humans (with our acidic digestive systems) unaffected.

But what good is this new Mutant Mosquito going to do, besides maybe inspiring the next SyFy channel original movie? It's far too early to say anything for sure, but some of the articles I've read are excited about replacing wild mosquitoes with the mutant construct. This seems pretty unlikely to me, given that the mutation reduces the mosquito's lifespan, and therefore its breeding window, by about 20%. That's not going to compete successfully with the wild mosquitoes.

The other argument is the 'What have we wrought?!?' conundrum, which is what I really wanted to explore here. No one is seriously suggesting that we should introduce these new mosquitoes into the wild, but the potential to take a lab-created organism and replace an existing one with it is fraught with interesting moral and ethical questions.

First, can we really predict every possible outcome? What if something goes horribly wrong once the mosquitoes are released? Isn't that what happened with the love bugs? Those stupid things are everywhere!

Ok, the story about the love bugs being created in a lab and accidentally released is amusing and all, but it's a myth. We have for a reason.

Also, genetically modified crops have been in circulation for several years. A majority of transgenic crops are herbicide- or insect-resistant, but others are designed to be resistant to extreme weather conditions or specific viruses and parasites that are problematic for farmers. Some crops are even engineered to be nutritionally fortified and have been used to alleviate chronic malnutrition. There is still some controversy over the use of these crops, especially in regards to the effects on biodiversity and potential for the modified DNA to spread to other plants in unpredictable ways. These are real concerns. Only time can really tell what the long-term effects will be, but the metaphorical wheel is in motion. So far, the results are positive. Nothing has gone horribly wrong, and this technology honestly gives me a glimmer of hope for the future.

Plants are obviously not on the same scale as genetically modified insects, though. Insects can crawl and fly and spread themselves across the globe. Malaria isn't the only disease spread by mosquitoes, either. West Nile Virus, Dengue Fever, Yellow Fever... it's not difficult to imagine one of these monsters filling whatever gap was left by the elimination of malaria. Still, we have to look at the very real danger malaria presents. If replacing the wild mosquitoes with this construct was a viable option, would it be ethical not to do so? How do we weigh the million actual lives that are lost every year to this parasite against the potential harm it could cause? I don't really have an answer to that, but I think it will be very interesting to watch the progress of transgenic crops in agriculture. Good or bad, the results of these forays into the genetic manipulation of our environment will likely set the precedent for the future.


  1. I don't think we should mess with mosquitoes.

    Two words: Love Bugs!

  2. I would argue your point that nothing has gone "horribly wrong" with the GM crops. They are fairly regularly being introduced into the crops of farmers who do not use them. Farmers who have, for generation after generation, saved their own seed from their own crops have had them altered by "accidental" cross pollination from a neighboring crop. This has left them open to litigation from corporations, namely Monsanto, for a breach of the rights that Monsanto's fairly unfortunate patent on their seed allows them.
    Of course, I realize that this a personal vexation of mine and not at all the type of "horribly wrong" you are referring to. Even if I think that corporations being able to essentially own the food supply is about the worst thing that could befall said supply.

  3. You're right Chris, I was thinking more in terms of 'SyFy channel original movie'-style horribly wrong, but that is a consequence of DNA contamination I hadn't considered. That's a legal issue that will definitely need to be addressed in a more comprehensive way in order for the technology to advance.

  4. I think the biggest danger here, is while genetic modification can create a biological defense in a much faster, punctuated, manner than nature - can it do so as steadily as nature.

    Its important to remember that nature does not exhaust its well of adaptation....ever. Our advancements tend to taper off and start again in spurts. This means that, if we can't change them all (which I doubt we can in this case) we are going to end up, in the end, creating more advanced problems. This has already been seen as foods that are genetically modified to resist insects have created adaptation among insects, and then stumped scientists as to how to fight off the new, more difficult variation.

  5. On that note, syfy originial movies are a boon to us all. I sat through all of Frankenfish, yeah I admit it.