What is the result of the experiment 'release genetically modified mosquitoes to the wild to prevent offspring from breeding' to eradicate mosquitoes?



Mosquitoes carry infectious diseases such as yellow fever , dengue fever , Zika fever , and malaria , so they are said to be ' the animals that killed the most humans in history .' Oxitec , a biotechnology company that develops technology to eradicate such mosquitoes, reported the results of an experiment that 'releases genetically modified mosquitoes to the wild so that offspring cannot reproduce.'

Biotech firm announces results from first US trial of genetically modified mosquitoes

As one solution to reduce the number of mosquitoes that transmit infectious diseases, the method of 'releasing genetically modified mosquitoes incorporating genes that kill offspring to the wild' has been attracting attention in recent years. Male transgenic mosquitoes (Aedes aegypti) developed by British biotechnology company Oxitec carry genes that are deadly to female offspring, and next-generation females born by mating with wild females are pre-breeding. It is said that only males can grow up after dying. By repeating mating in this way, many males with genes that are lethal to females are born, while a large number of females die, and as a result, the population of Aedes aegypti can be reduced.

In order to confirm the effect of the developed genetically modified mosquitoes, Oxitec started an experiment to actually release the genetically modified mosquitoes in the wild in April 2021 in Florida Keys , an archipelago on the southern tip of Florida, USA. The research team set up a box containing the eggs of the recombinant mosquitoes and collected data such as the range of movement of the recombinant mosquitoes, the period during which the lethal gene was passed on to the offspring, and the eggs laid by the breeding individuals. A series of experiments lasted for seven months, and a total of 5 million transgenic mosquitoes were released into the wild.

Large-scale experiment to release tens of millions of genetically modified mosquitoes to be conducted in the United States --GIGAZINE

And in April 2022, Oxitec reported the results of this experiment in a webinar held by the Florida Keys Mosquito Control District (FKMCD), a mosquito control organization operating in the Florida Keys. Was done. '

Oxitec claims that the results of the experiment confirmed that male Aedes aegypti hatched from the installed eggs flew 1 hectare (100 m square) around the box installation site and mated with a wild population. In addition, the research team brought back 22,000 eggs laid around the box, hatched them in the laboratory and observed the progress, before all the females inheriting the lethal gene became adult individuals. It was confirmed that he died.

We also found that the lethal gene survived for 2-3 months, or about 3 generations, in the Florida Keys wild population and then disappeared. Aedes aegypti, which has a lethal gene, was not found at a distance of 400 m or more from the point where the box was installed, even after several generations have passed since the first generation. Oxitec says the experiment has continued to investigate for 10 weeks since the last discovery of a mosquito with a lethal gene.

'I like the experimental methods Oxitec is doing. They are experimenting in a systematic and thoughtful way. I'm encouraged by this,' said Thomas Scott, an entomologist at the University of California, Davis. But they have a lot of work to do. '

This experiment does not show how well the method of releasing transgenic mosquitoes controls wild populations, and Oxitec plans to collect data by conducting a larger study at the Florida Keys. It also plans to conduct an experiment to release genetically modified mosquitoes in

Visalia , California.

However, these expanded studies do not evaluate 'whether Oxitec's method reduces the spread of infectious diseases carried by Aedes aegypti.' 'Oxitec cannot test to show that this is actually affecting public health,' Scott said. 'The Florida Keys don't have enough Aedes aegypti-borne virus.' .. There is no suitable place to do this kind of research in the United States, including the Florida Keys, so it seems that it is necessary to make expensive investments and research in other regions to make an accurate evaluation. In addition, it cannot be simply said that 'a decrease in the number of Aedes aegypti will reduce the transmission of infectious diseases,' and Scott points out that many types of mosquitoes other than Aedes aegypti also inhabit.

Still, FKMCD Executive Director Andrea Real said, 'We have dealt with multiple outbreaks of the disease, so we must do everything we can to protect the local people and the economy. We are looking at tools that may help prevent infections, 'he said, looking forward to Oxitec's method.

According to the FKMCD, 68 people were infected with dengue fever in 2010 in the Florida Keys, and 72 people were infected in 2020. Scott argues that FKMCD and Oxitec's efforts to interact with the community are particularly important, as they also sought the opinions of the local community during the Oxitec experiment and held a referendum in 2016. Did.

in Science,   Creature, Posted by log1h_ik