Holy crap! This is so clever!!

A synthetic sex ratio distortion system for the control of the human malaria mosquito

Component #1– Anopheles gambiae, the kind of mosquito that is notorious for spreading malaria.

Component #2– I-PpoI, a protein that ‘sees’ a specific DNA sequence, and cuts it. aka, a homing endonuclease. It was originally found in slime mold.   :-D

It might seem as if there is no way these two components could come together in any meaningful way.

But when you are an evil scientist, anything is possible!!

 

It turns out that there is a DNA sequence on the X-chromosome of the mosquito that the homing endonuclease recognizes. Unlike restriction enzymes, where the DNA match has to be (pretty much) perfect, there is some wiggle-room with homing endonucleases (the mosquito DNA isnt a *perfect* match, but its good enough).

So, if this enzyme was present in mosquito cells, it would slice the X-chromosome in two.

That is not overly helpful.

If you start slicing up the X-chromosome, the mosquitoes would be non-viable. Male and female. The point isnt to kill mosquitoes, here.

So, the researchers genetically modified the enzyme so it would only be expressed during spermatogenesis, and it would have a really short half-life (it would break-down and become non-functional relatively quickly).

Translation: Male mosquitoes that had this gene engineered into their genomes would only make sperm with Y chromosomes. Very few or no X chromosomes. Meaning mostly all of their offspring would be male. The enzyme would be degraded by the time fertilization occurred, so it shouldnt accidentally slice up the necessary X-chromosome from mom-mosquito.

Lots and lots of viable baby male mosquitoes.

Male mosquitoes do not feed off of humans, meaning they dont transmit malaria or other pathogens.

And, having males dominate the progeny means that the mosquito population would go down (whereas having mostly females would cause the population to boom). The idea to mess around with mosquito population sex ratios to control population size has been around since 1966. This is just the first time in history we have had the technology to carry it out.

 

Of course there are concerns about ‘resistance’ (the mosquito populations evolving around the genetic modification), which this paper addresses. And they didnt address the impact a smaller mosquito population would have on the populations of other organisms (somebody has to eat them, right?). But considering the number of people who get sick and die from malaria every year (not including all the other mosquito-born pathogens!), this might be a great first-step in a positive direction.

Comments

  1. #1 Jimmy Senkov
    June 11, 2014

    This will enhance Global Warming. Just ask Mr. Laden or Mr. Connolley.

    Sorry…I just too pleasant to see an article here that is not anti-scientific.

  2. #2 Carl
    June 11, 2014

    Actually, the GMO process will somehow produce sterile monarch butterfly’s; or at least someone will make that claim.

  3. #3 Will
    June 12, 2014

    Oh look, GMOs being used for exactly what theyre ALWAYS used for: Population Control

  4. #4 Dan H.
    June 12, 2014

    The other thing to remember regarding malaria is that it is not just a disease of mammals, but of mosquitoes as well. That’s the other route for defeating malaria: GMO mosquitoes which are resistant to infection with malaria parasites. Malaria doesn’t do mosquitoes much good either; it isn’t a passive guest but an active infection, so insects that don’t get sick ought to out-compete the ones that do suffer from malaria.

    As I recall, someone has already engineered malaria-resistant mosquitoes, but nobody quite has the nerve to release a GMO into the wild.

  5. #5 Jim Thomerson
    June 12, 2014

    http://www.ars.usda.gov/is/timeline/worm.htm

    This is a description of the eradication of the screwworn fly. They use x-rays to produce sterile males.

  6. #6 william
    wisconsin
    June 17, 2014

    Mosquitoes are an important part of the ecology and food chain. BAD idea

  7. #7 fusilier
    June 17, 2014

    Nothing has changed. In ’69 (when George Craig was my undergrad entomology prof at Notre Dame) various knuckleheads were yammering about how this paper was a biological warfare proposal to spread yellow fever.

    fusilier

    James 2:24

  8. #8 Ashley Davidson
    June 25, 2014

    The idea is really clever, but I also think our knowledge in genetics isn’t enough to predict possible bad outcomes. Maybe it’s too early to experiement with this.

  9. #9 Robert Gotschall
    June 26, 2014

    Yeah I am wondering what would happen if the genetically modified enzyme didn’t break down as quickly as planned and the few remaining mosquito females somehow reintroduced it into humans resulting in no human females. Sounds like the storyline for _Legend_ don’t it? :)

  10. […] are many genetic engineering research projects ongoing. Let’s judge each on its merits. Here is one that will control the mosquito population to prevent them causing malaria. Here is one that […]

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