The experiment failed
Geneticists reported a failure in the fight against malaria with the help of GM mosquitoes
Sergey Vasiliev, Naked Science
Biting mosquitoes are not just unpleasant bloodsuckers, but also carriers of many diseases. The main one in terms of scale and danger remains malaria, which claims hundreds of thousands of lives every year. Global warming allows infection-carrying mosquitoes Aedes aegypti is spreading more widely from its "primordial" tropical range.
One of the most innovative and promising methods of combating this threat is the use of genetically modified mosquitoes. Released into nature in large quantities, GM males should compete with ordinary wild insects by mating with females, but they are not able to leave viable offspring.
According to calculations and preliminary tests, the use of such a program in certain regions can reduce the number of mosquito populations by up to 85%. And along with them, the spread of yellow fever, Zika disease and, of course, malaria will be limited. At the same time, insects born from GM fathers should not live to reproductive age, and their genes will not be able to spread in the population.
Such GM mosquitoes were obtained by Oxitec biologists, and their "field" tests were approved by the US Food and Drug Administration (FDA). One of them took place in Brazil, in the vicinity of the city of Jacobino, where about 450 thousand GM males were released into nature every week for 27 months Aedes aegypti. The team of Yale University Professor Jeffrey Powell presented the results of this work in an article published in the journal Scientific Reports (Evans et al., Transgenic Aedes aegypti Mosquitoes Transfer Genes into a Natural Population).
Tracking the course of the experiment, geneticists monitored the DNA of both GM mosquitoes and wild ones, taking DNA samples immediately before releasing the insects into the wild, and then after 6, 12, 27 and 30 months. Contrary to all calculations, the genes of laboratory mosquitoes not only did not disappear, but eventually spread in the local population. About 3-4% of their offspring survived and produced their own offspring, and this turned out to be enough.
Initially sharply reduced, the local mosquito population recovered after 18 months. Scientists suggest that the females somehow learned to identify "defective" GM insects and avoid mating with them. Well, then the effects of the spread of new genes began to manifest themselves.
Now, not only local heredity is found in this population, but also strains from Cuba and Mexico that were used to produce GM males. Geneticists suggest that according to the results of the experiment, the population has become even more stable, since it has increased its genetic diversity.
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