GMO: Suicide Mosquitoes

By Emily Stone

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The Suicide Mosquitoes Start

In order to understand this GMO we first need to start off with what the Aedes aegypti mosquito carries. It carries a virus called Dengue virus that because of these mosquitoes about 50-100 million people a year are infected with dengue virus every year. There is no medicine or vaccine that can treat or cure Dengue virus. And the mosquitoes have become resistant to pesticides. So Luke Alphey from Oxitec, found in London, with a team of scientists set out to find a way to stop mosquitoes from infecting people. They finally found a way to stop the spread of Dengue virus.

Creating the Suicide Mosquito

The scientists found a protein called tTA that would communicate with other proteins that are essential for controlling cellular activity, the communication causes the cells to not activate genes that mandatory for survival. How did they get the protein into the mosquitoes? Well its not all that easy of a task. First they start off with a single mosquito egg, which is about 1mm long. Scientist then inject an incredibly small amount of DNA that contains the deadly protein, using a special glass needle. Not all injections are successful though, in a batch of about one thousand only one egg will have the protein incorporated into the genome of the mosquito. Some have the DNA for the protein but it is not activated. While the mosquitoes with the protein meshed into their genome are reproduced with others and the gene is passed on to the offspring. The tTA protein is not the only thing injected into the eggs though scientists also put a fluorescent gene (DsRed) into the eggs so that they can tell which mosquitoes now have the protein in them.

Off to Work

What I find interesting is that in order for the mosquitoes to live in the lab the scientists give them a fake vaccine that neutralizes the effects of the protein. The fake vaccine is called tetracycline. Something else that is quite intriguing is that the mosquitoes must be transported to their location as larvae because adults can't be transported safely. Their wings and legs get all tangled up and its hard to contain them. The larvae also don't have to be injected with the fake vaccine because the protein doesn't come into affect until it reaches the pupae stage of life.


The first test of these suicide mosquitoes was done in Cayman Islands in the Caribbean. It is very important to make sure that only males are released. If males and females were released together they would mate with each other and reduce the chances of the protein being passed to wild mosquitoes. The Oxitec male mosquitoes accounted for just under 20% of the male population and the amount larvae that had the deadly protein was 10%. The test was a success, and they moved on to putting some of the mosquitoes in Brazil. They released millions of the male Suicide Mosquitoes and now a very impressive 84% of the larvae carry the lethal protein.

The good and the bad

The Good:

There is actually another way that the Oxitec scientist could have gone about decreasing the amount of mosquitoes that carry Dengue virus. It's called Sterile Insect Technique (SIT) which calls for male insects to be sterilized using radiation. The males would still have sperm and would be able to mate but the offspring wouldn't live very long. But because of the high amount of radiation the males would be very weak and females would not mate with them and that's if the males didn't die while being transported. The way that Oxitec has created doesn't harm the males used it is just an addition of a protein gene into the mosquito eggs. This way has worked really well and has reduced the amount of mosquitoes with the dengue virus significantly. The GMO also stops the worry of insects becoming resistant to pesticides.


The Bad:

As always there is somethings that people fear when it come to GMOs. In this instance people fear the creation of a super bug that could cause environmental and agricultural havoc. Also the insects may be able to evolve a resistance to the lethal protein or might be able to recognize and avoid insects with lethal genes. But it is much harder to be done than say pesticide resistance and can be overcome by changing the strain of DNA put into the mosquitoes.

Sources

Nicholls, Henry. "Swarm Troopers: Mutant Armies Waging War in the Wild." - Life. N.p., 12 Sept. 2011. Web. 26 Apr. 2015. <http://www.newscientist.com/article/mg21128291.700-swarm-troopers-mutant-armies-waging-war-in-the-wild.html?page=3#.VT1B4fnF91Y>.


Paoli, Julia. "Genetically Modified Mosquitoes Pave the Way for Dengue Fever Prevention." Nature.com. Nature Publishing Group, 15 Sept. 2014. Web. 26 Apr. 2015. <http://www.nature.com/scitable/blog/viruses101/are_modified_mosquitoes_the_future>.