Gene Responsible for DEET Resistance Believed Dominant in Mosquitoes

Unlike the active ingredients in most household products, DEET holds a special place in our hearts. In as much as any mosquito repellent component can be, DEET is constantly in the news. The lambasting it has received throughout the years, however, is mostly unwarranted. Under household doses (if you bathe in the stuff I think you might be in trouble), DEET doesn’t cause birth defects or induce seizures. Some people die of DEET poisoning every now and then, but people die from huffing gasoline too. No need to throw the baby out with the bath water. DEET prevents the transmission of malaria, West Nile Virus, and many other potentially lethal diseases. In the developed world, where the fear of dengue fever takes backseat to the more relevant usage of DEET as employed when enjoying a picnic or going for a summer walk, it is easier to view insect repellent as a convenience rather than a necessity. But we do take our convenience very seriously. It’s especially unfortunate for everyone then that researchers from the UK found breeding DEET resistant populations of mosquitoes to be remarkably easy, so simple that it suggests that DEET resistance is, in fact, a dominant gene (or set of genes) in the larger mosquito genome.

Through a regiment of selective breeding, the researchers produced strains of Aedes aegypti mosquitoes in which half of all females were unaffected by DEET. The relative ease with which they did so means that it’s quite likely DEET resistance is passed from generation to generation if only one parent has the gene responsible. While scientists did not pin down the actual sequence of DNA conferring resistance, or the process by which it might do so, they do have some promising leads. Certain olfactory cells which go haywire in normal mosquitoes in the presence of DEET respond less dramatically in the resistant population, and likely play a role in the efficacy of the pesticide.

Regardless, this research suggests we can expect a largely DEET resistant mosquito population in the near future. While similar resistance accumulated against the insecticide DDT, this is the first published study to indicate this worrisome trend developing with DEET. Brands like Off! and Bug Barrier will need to move on to other active ingredients as the efficacy of their product wanes. Whatever new bug spray is developed will surely reek with the same stench of public rumor and unverified accusation, but its inventors would do best to not focus on all of that. The problem they need to overcome will be far more challenging: preventing evolution.


~ by Wil Finley on May 5, 2010.

One Response to “Gene Responsible for DEET Resistance Believed Dominant in Mosquitoes”

  1. An all around great blog post…

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