Good news for climate doomsayers – genetic modification wipes out mosquitoes in the lab

We have been told time and again that climate change will enhance mosquito populations, thus bringing increased incidences of disease such as malaria and dengue fever.

Fortunately, science is ahead of the climate-to-mosquitoes issue (even if it may be overblown) as we see in this story.


Gene editing wipes out mosquitoes in the lab

Researchers have used gene editing to completely eliminate populations of mosquitoes in the lab.

The team tested their technique on the mosquito Anopheles gambiae, which transmits malaria.

Anopheles gambiae Image: Wikipedia

They altered part of a gene called doublesex, which determines whether an individual mosquito develops as a male or as a female.

This allowed the Imperial College London scientists to block reproduction in the female mosquitoes.

They want to see if the technology could one day be used to control mosquito populations in the wild.

Writing in the journal Nature Biotechnology, Prof Andrea Crisanti and colleagues report that caged populations of Anopheles gambiae collapsed within 7-11 generations.

Dr Crisanti said:

“2016 marked the first time in over two decades that malaria cases did not fall year-on-year despite huge efforts and resources, suggesting we need more tools in the fight.”

The approach falls within a category of genetic engineering known as a gene drive. It describes technologies that spread a gene or particular suites of genes through a population.

The researchers used the gene editing technique known as Crispr to modify a part of the doublesex gene that is responsible for female development.

More here


The paper: https://www.nature.com/articles/nbt.4245 (open access)

A CRISPR–Cas9 gene drive targeting doublesex causes complete population suppression in caged Anopheles gambiae mosquitoes

Abstract:

In the human malaria vector Anopheles gambiae, the gene doublesex(Agdsx) encodes two alternatively spliced transcripts, dsx-female(AgdsxF) and dsx-male (AgdsxM), that control differentiation of the two sexes. The female transcript, unlike the male, contains an exon (exon 5) whose sequence is highly conserved in all Anopheles mosquitoes so far analyzed. We found that CRISPR–Cas9-targeted disruption of the intron 4–exon 5 boundary aimed at blocking the formation of functional AgdsxF did not affect male development or fertility, whereas females homozygous for the disrupted allele showed an intersex phenotype and complete sterility. A CRISPR–Cas9 gene drive construct targeting this same sequence spread rapidly in caged mosquitoes, reaching 100% prevalence within 7–11 generations while progressively reducing egg production to the point of total population collapse. Owing to functional constraint of the target sequence, no selection of alleles resistant to the gene drive occurred in these laboratory experiments. Cas9-resistant variants arose in each generation at the target site but did not block the spread of the drive.

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70 thoughts on “Good news for climate doomsayers – genetic modification wipes out mosquitoes in the lab

  1. My prediction is that the mosquito will be the next ‘endangered species’ in need of protection.
    Fines implemented if you slap one on your arm.
    Prison sentence if you crop dust your field.

    • You beat me to it and the campaign will borrow from the manual for GMO pressure tactics. See the decline of Monsanto if there are any questions. The best thing that could happen is if China steals the technology and gives it to many countries in its drive to influence developing countries. Americans and EU citizens could visit the mosquito-free zones.

      • The best thing that could happen is this gets implemented without the Chinese stealing even more intellectual property.

    • As ridiculous as it sounds, I believe you may be right. I believe environmental and liberal extremists don’t want to save people, they only want to appear to be in the business of helping people, while “saving the planet” (means taking control over the lives of the entire global population). I believe they want to reduce the population by several billion, and to have absolute control over those remaining. So stopping mosquitoes from spreading malaria is anathema to their goals.

    • It’s the unknown and unknowable unintended consequences that might give us pause before we barge ahead with this.

      CRISPR is an astonishingly powerful tool. Or a double edged sword.

      • Bugs are hard to beat.

        Anopheles gambiae is liable to find a way around this method of vector control, as hundreds of pests have evolved resistance to pesticides and other control methods.

      • You’re right but one of the known side effects that at least some enviros will use to try and stop making “Frankenskeeters” will be collapsing food chains.

    • What will dragonflies eat? They devour mosquitoes! Think of the dragonflies!! #dragonfliesmatter!!!!!

      (Don’t take the fun out of this by giving me a list!!!)

      • Sara,

        OK, I won’t list all the other insects which dragonflies eat, but will note that their giant griffinfly predecessors got along fine and reached their largest size before mosquitoes ever evolved.

        However dragonflies might be considered adapted to hunt mosquitoes and another group whose name I dare not mention.

    • I went to a climate protest a few years back with a big sign that said “Save The Mosquitoes”. I borrowed a long hair wig and with my winter beard, looked like a proper vagrant. I can still remember some of the looks I got from the faithful, wondering whether they should join in with me, and some even congratulating me for doing my part. But none looked at me with suspicion. I was looking to hopefully shame them by appearing so ridiculous, but apparently none thought that saving the mosquitoes was not a noble cause. For the record, I would very much support the gene editing command to eradicate mosquitoes from the face of the good Earth. (ctrl-alt-delete) And I really mean that!

  2. Might help reduce populations until the few surviving mosquitoes evolve a new sex determination system. Or until the nonfunctional, modified gene mutates into functionality.

      • I hope it does “work too fast,” but considering that these mosquitoes are found in abundance over vast swaths of the tropics, and sometimes beyond, it seems dismayingly unlikely that we can do more than thin their numbers, probably concentrating on the areas of densest human population.

    • Latitude,

      You’re probably right, but flies are capable of evolving rapidly. With maybe billions of A. gambiae individuals per two-week generation, and each bug with multiple mutations, hard to say, IMO.

  3. I wonder if the Doublesex Gene becoming active gives the Mosquito the desire to
    Go F itself
    This would certainly drive down the availability of Mating to produce the next generation.

    • An all male mosquito population wouldn’t contain any blood-suckers. Only the females feed on blood, in order nefariously to get protein to make their eggs.

  4. The fact that exon 5 is so highly preserved in mosquito species suggests that the technique will also work on Anophelus Aegypti, the Yellow Fever vector.

    • Actually no, the yellow fever mosquito is Aedez aegypti. The genus Aedes is in a different subfamily (the culicinae) from Anopheles (subfamily Anophilinae). I doubt the CRISPR-Cas9 Gene drive system will affect Culicinae mosquitoes.

  5. Great plot for a new horror movie: Genetically modified mosquitoes transmit infertility gene to other species leading to next great extinction event.

    • Craig,

      If the event were limited to mosquitoes, the horror would be limited as well. Indeed, rejoicing might ensue.

      The only insect sex determination system about which I know anything is D. melanogaster’s, which is apparently restricted to that species and a few others closely related to it in the highly speciose genus Drosophila.

    • Even better horror movie: GM mosquitoes get exposed to radiation from Fukushima and transform into giant HIV-transmitting monsters while farting out vast quantities of CO2 that quickly begins to turn the world into Venus!

  6. I wonder if this technique would work on all of the various genders of the species americanus liberalis democratis?

  7. Seems daft, as said, they are an important part of the food chain in water and air.

    All these diseases can be wiped out by other means.

    • Mr. Grim,

      Mossies are important to many animals higher up the food chain, but there is rarely a shortage of other flying and crawling insects. Maybe there is a bird, bat, fish or other insectivore dependent on mosquitoes, but as a general rule, they’re not picky. Just about any insect or arachnid will do, plus other small prey.

      North America’s common little brown bat eats a lot of mosquitoes, it’s true, but also gnats, hoppers, midges, caddisflies, mayflies, moths, wasps, small beetles and, occasionally, spiders. They do rely upon aquatic-hatched insects like mossies, however, which is why they tend to roost near bodies of water. But other aquatic insects are on their menu. Annoying midges are often mistaken for mosquitoes.

      Practically speaking, though, we’re unlikely ever totally to eradicate mosquitoes. And even if we did, something very like them would soon evolve, as happened among the 6000 insect species endemic to Hawaii, which also boasts a bountiful supply of unique spiders.

  8. The way to prevent mosquito vectored diseases has be well known for more than 2,000 years.

    The Roman Empire of Classical Antiquity did not have a problem with Malaria because they knew how to drain swamps and they did it. No swamps, no mosquitoes, the life cycle of the plasmodium parasite is broken, and Malaria disappears as a pandemic.

    “Environmentalists” oppose draining swamps because they think swamps are “ecologically important wetlands”. It is part of their campaign to impoverish, immiserate, and demoralize the lower classes.

    • don’t need no stinkin’ swamps… gutters, planters, storm drains, just a low spot in the yard. Mosquitos love ’em all.

    • “The Roman Empire of Classical Antiquity did not have a problem with Malaria ”
      —————
      Err no ! Even Rome, with best-of-the-world sanitation system (for the Antiquity but still an abomination compared to modern standards) was frequently hit by massive malaria bouts, let alone the Roman Empire.

  9. Of course if scientists are able to wipe out the Maleriaan mosqquito, then this would lead to a massive increase in the population of countries which presently suffer from maleria. So what do we then do about this particular problem ?

    MJE

    • MJE,

      In 2016, there were 216 million cases of malaria worldwide, resulting in an estimated 445,000 to 731,000 deaths, if WHO’s numbers are to be believed. About 90% of both cases and fatalities occurred in Africa.

      A 2005 article in Lancet estimated that in Africa, the disease caused losses of US$12 billion a year due to increased healthcare costs, lost ability to work and negative effects on tourism. So, IMO, concerns about overpopulation shouldn’t stop attempts to control or eradicate malaria. When people’s lives improve, a demographic transition happens, limiting population growth naturally and humanely.

      I favor eradicating A. gambiae if possible. Also A. aegypti, the vector of yellow fever. They’re just two of some 460 recognized species in genus Anopheles. But I suspect it’s not feasible to do so.

      • Oops. Aedes aegypti isn’t an Anopheles species. Aedes is even more speciose than Anopheles, with some 700 species in subgenera.

        My bad.

        But I’m still in favor of getting rid of it.

        • Aedes (Stegomyia) aegypti would be a good candidate for eradication. It is largely dependant on humans – wrigglers lives in small accumulations of water around people and females likes to bite people whenever they can. They are very competent vectors of numerous nasty arboviruses such as Yellow Fever, the dengues, Chikungunya, Zika and more. Also, if the Asian Tiger Mosquito (A. (S.) albopictus) could be taken out at the same time, that would be good as they are almost as bad. Neither is likely an important food for any wildlife and both are 1st World problems (the US has allowed both to establish again after once having them under control and Australia seems to be following suite). Who could complain about wiping out these villains? This last is sarc, alas.

          • I’m all for eradication.

            There would be little to no loss of genetic information, given how speciose are the genus and subgenus. I don’t know if any other species features the characteristic white bits, but I’m willing to give those up.

            Whatever eats them will still have lots of other mosquitoes to consume.

    • Michael: DDT was incredibly effective against the Malaria Mosie, not to mention fleas and ticks that felled more Allied soldiers than bombs and bullets in WWI. Rachel Carson wrote her ill-informed book Silent Spring that led to the Eco movement, creation of the EPA and as their first tie-dyed order of business, the ban of DDT production and use. Hippies were proud to support Carson and Ehrlich’s Zero Population Growth beliefs while millions of brown people died from Malaria, Dengue and others. Nice people.

      • The problem with DDT is that mosquitoes rapidly developed resistance to it, especially as at the time it was being widely used in agriculture, it was rapidly becoming useless because of overuse. DDT was not banned but its widespread use was, it’s still available for use in dwellings where it is still effective.

  10. Re. my comment about one of the reasons for over population of countries such as Africa is thaat its the belief on the par t of faamilies that they must have large families to allow for deaths in the family, and still have some to car e for their parients in theeir old age.

    T he solution of course is as occurred in the Western countries is to make the country a lot richer, this can only occur if energy, most ly in the form of cheap elect ricitry occurs.

    As many such countries have large amounts of fossell fuel it should be developed and and the plus is that the ext r a CO2 produced will improve food production too.

    So ove rall health improves and hoefully as in the West the polulation will dec rease.

  11. The bleeding hearts and other Social Justice Warriors/ useful idiots will be up in arms- how dare they declare war on their fellow parasites!

  12. I’m no greenie but this scares the heck out of me. The web of life is an interconnected continuum. Sure, attempt to fix things but “first do no harm” (primum non nocere)!

    I fear the next headlines will read:

    * Earth Dying
    *Total Ecological collapse
    *Mosquito eradication big mistake
    *End of biosphere caused by mosquito
    *They knew not what they do!

    Most human genes and insect genes are the same and function very similarly. In fact 60% of human DNA is identical to that of a fruit fly!

    If you are going to mess with the code, please be very careful ;-(

    • “The web of life is an interconnected continuum.”
      ———-
      Oh no, not that “interconnected” claptrap. Look it up, you’ll see it’s pure greenie propaganda based on 100% claim and zero science.

      • Yeah I agree, like any methodology it is limited. It was a stretch to use it but it served the purpose of illustrating that we are not as far removed from insects than is immediately apparent! 😉

        I will look it up, as I’m from that generation where that particular notion was the standard biological science propaganda of the time.

  13. …Researchers have used gene editing to completely eliminate populations of mosquitoes in the lab….

    In the lab, I could wipe out the entire sample population with a rolled-up copy of the report.

    ….This allowed the Imperial College London scientists to block reproduction in the female mosquitoes…

    Have they thought of encouraging feminism and fashionable lesbianism amongst the mosquito population?

  14. Malaria has already been ‘eradicated’ at least once in lab, that I know of.
    Back in 1990s I went to a very interesting departmental seminar given by a scientist working for an anti-malaria charity (I cannot recall the name). The speaker recounted the story of an anti-malarial drug developed by Glaxo. The compound eliminated the parasite completely and efficiently in all of the regular laboratory tests. More importantly, there was measurable development of drug-resistance by the parasite, even over long periods of time using stringent tests (even the size of the flask or the test animal can influence the course of development of drug resistance).

    The bad news? In human subjects the drug exhibited serious photo-toxicity. So serious that that approach was abandoned.

    Personally, I would be prepared to live in a dark cave for several weeks if I needed treatment for malaria, but I guess that is not really an option for most Africans. Still, as a medicinal chemist, I was surprised that the compound hadn’t led to development of similar ones without the side effects. I think that was what the speaker’s charity was attempting but I never heard anything more about it. Pity.

  15. Instead of another 10 years of lab studies, perhaps there is some small island nation willing to act as an outdoor, real-world laboratory and the mosquitoes can be wiped out for them. Then maybe I can go live there. I hate those things.

  16. Just a couple of comments. Some will argue that eradicating Anopheles Gambiae would endanger those other species that eat mosquitoes. The counter is that there are many mosquito species, people and animals would continue to be bitten, only the malaria carrier would be affected.
    It seems that they’ve addressed the issue of keeping it within Anopheles Gambiae only so it doesn’t wipe out other species. I’ll assume they’ve confirmed that there is no cross-breeding.

    • Today it was hell outside with the Asian Tiger mosquito after the rains. Ten years ago there were none. An invasive species without any controlling enemy. That genetic technique would be a great relief in this side of the Med.

    • https://www.vectorbase.org/organisms/anopheles-gambiae

      “Anopheles gambiae senso stricto is the primary mosquito vector responsible for the transmission of malaria in most of sub-Saharan Africa. It is a member of a species complex that includes at least seven morphologically indistinguishable species in the Series Pyretophorus in the Anopheles subgenus Cellia. Anopheles gambiae feeds preferentially on humans and is one of the most efficient malaria vectors known. Anopheles gambiae senso stricto is now known to consist of two genetically distinct forms or incipient species, known formally as the A. gambiae M and A. gambiae S forms. Colonies of these two forms have also been sequenced, assembled and provided here on VectorBase as the A. gambiae Mali-NIH (M) and A. gambiae Pimperena (S) genomes.”

  17. “genetic modification wipes out mosquitoes in the lab”.
    I won’t need to cover myself in deet before I walk into a lab anymore. Woo Hoo!

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