One of the interesting side effects of the new DNA technologies is the ability to tweak existing organisms to make them more what we would like. The most recent example involves releasing mosquitoes engineered to produce sterile offspring. Their larva are supposed to die before becoming adults.

Since it’s the adult females that do the biting, it’s hoped this will greatly reduce transmission of Dengue Fever.

“In April, the Institute for Medical Research in Kuala Lumpur indicated that it might release millions of male Aedes aegypti mosquitoes that have been genetically modified to produce offspring that die in the larval stage. The release of enough of the sterile males would theoretically swamp fertile wild-type competitors and crash the population…..

Oxitec integrated a genetic element, LA 513, into the DNA of the mosquitoes. This genetic modification kills any offspring in the larval stage if they are not fed the drug tetracycline. In the lab, the mosquitoes are fed tetracycline and grow in the millions. In the wild, the modified gene kicks in, and, in theory, would be able to crash the local A. aegypti population (H. K. Phuc et al. BMC Biol. doi:10.1186/1741-7007-5-11; 2007).”

The two big questions are “Is this safe?” and “will it work?”

The mosquitoes are unquestionably genetically modified organisms, and that is scary to a lot of people. It seems like this would be relatively safe since the mosquitoes are rendered non-functional by having a gene inserted that makes them dependent on an antibiotic to finish development–which they won’t get in the wild.

Will it work? Only time will tell. I very much hope it does work, since the potential for alleviating human suffering is huge. However, the critical element in all sterile insect releases is how well the sterile males compete with wild males. If the wild, unaltered males are more attractive, or better competitors, then they will mate with the females.

Preliminary studies indicate these GM males do well against wild mosquitoes in mating with females.

Keep your fingers crossed.

Posted by Gwen Pearson

Writer. Nerd. Insect Evangelist. Have you heard the good news? BUGS!


  1. Something tells me that selection against the sterile males is gonna be pretty intense…

  2. Didn’t they create female mosquitoes?

  3. Pretty cool.
    Who knows what more to come. What if some genious would create some genetically modified mosquitoes that’s bite can kill people, that can be used against enemy or enemy countries. How would that be stomached!!!??
    All genetical mutation should be stopped

  4. “All genetical mutation should be stopped”

    To do that, one would need to eliminate all UV sunlight from reaching the earth. But even then, those pesky little nucleotides still have the habit of spontaneously rearranging themselves anyway.

    Or perphaps you’re referring specifically only to anthropogenic, non-random mutagenesis – an essentialist viewpoint that prefers things stay the way they are because that’s the way they are. I guess if God didn’t want people to die from malaria, he wouldn’t have created it to begin with.

  5. We live in a fragile world. You cant draw simple cause and effect scenarios. No one knows what the effect of nearly wiping out the entire population of any one species will be. I don’t think “anthropogenic, non-random mutagenesis” is a good idea.

  6. Actually, you don’t need to wipe it out.
    You just have to lower the population enough that the disease transmission is lowered.

    Once the pool of infected vectors is reduced (diseased people for new mozzies to bite), you could in theory let the mosquitoes come back.

    I think GM is ok in *some* circumstances.
    Roundup-ready corn–no.
    This experiment–maybe.

    Animals are a lot less likely to go around sharing new genes than plants are.

  7. There have been several recent papers presenting strong genetic evidence that homoploid hybrid speciation is much more common in animals than previously believed – especially in parasitic taxa. If true, and if the possibility to “share” genes is an a priori criterion for whether GM is okay or not, then this mosquito research is also off limits. I disagree with this approach, but rather think decisions should be made case-by-case based on full consideration (are there related wild species in proximity, if so will the “shared” trait provide a selective advantage, etc.). Blanket edicts have the great potential to solve problems that don’t exist while preventing true benefit from being realized.

  8. I will have to go look for those papers then, Ted.
    I’m not a molecular person, so don’t keep up with those journals.

    I can definitely see the potential for host/parasite transfer…..hmmm.

  9. […] picture of a gynandromorph moth. If you’re in a bitey mood, you’ll find a new face of struggle against mosquitoes on her blog, or you’ll be delighted by some more de-licious […]

Comments are closed.