Which tribe is originally from Florida

Florida: genetic engineering against yellow fever mosquitoes

The classic SIT is an extremely successful method, with which the tsetse fly was exterminated on Zanzibar and which is still used daily to combat the Mediterranean fruit fly. This originally comes from Kenya, but has now spread to all five continents and is a feared pest in vegetable and fruit growing. “The largest breeding facility is in Guatemala, where up to four billion males are bred every week. That's around 20 tons of insects, ”explains Schetelig. In the US, millions of animals are released every day at hotspots such as airports and ports to prevent outbreaks. In Europe, too, sterile male Mediterranean fruit flies are released daily; the breeding facilities are located in Israel and Spain.

"The question is: what alternatives do we have?"
(Marc Schetelig)

“The problem with this method is that some of the irradiated males are not completely sterile. However, the radiation dose cannot be increased at will, because then the damage will increase. You irradiate the whole animal, including the brain, and if the behavior of the factory males deviates from the norm, free-range females don't want to know anything more about them «explains Wimmer.

Over time, the manipulated genome disappears by itself

Another catch is that the classic SIT cannot be applied to every species of insect as well as it is with the prime example of the Mediterranean fruit fly. "You need a suitable system in order to be able to breed only males en masse," explains Schetelig. This is where genetic engineering comes into play, with which the female sex uses genetic tricks like that tTAV-System can be switched off, so to speak.

Oxitec's OX5034 mosquitoes differ in one essential point from the classic SIT animals: The OX5034 males used are just not sterile. They are supposed to be killing the female tTAV-Generally passed on to the next generation. This is desirable in order to reduce the population in the course of several mating cycles without having to continuously release more males - which is absolutely necessary in classic SIT. After a few generations, the OX5034 males disappear from nature, as Mendelian rules apply, i.e. only half of the male offspring inherit the OX5034 genome.

Oxitec's release plans counter the mistrust of various environmental groups in Florida. It was not until autumn 2019 that a publication in the journal »Scientific Reports« made negative headlines worldwide: Oxitec's transgenic mosquitoes would spread in Brazil, was read in a number of media. "The work was misleading," says Wimmer and is not alone with his criticism - including the undifferentiated representation in serious media. The study found no negative or unexpected effects on humans or the environment, but it was speculated. The editorial team of "Scientific Reports" has reacted in the meantime: in mid-May 2020 they published a statement. Six of the ten authors of the controversial study agreed to the corrections listed in their "Letter of Concern".

In Brazil, Oxitec's attempts are met with a high degree of approval. The decisive factor is the level of suffering caused by the Zika and dengue infections, says Wimmer.