Pros and Cons of Genetically Modified Mosquitoes

A UK research team says it has found a way to effectively attack the transmission of diseases such as Zika, chikungunya and yellow fever with "killer mosquitoes". What is it about?.

Mosquito perched on a person

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LatinAmerican Post | Christopher Ramírez

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Leer en español: Pros y contras de los mosquitos genéticamente modificados

Genetic alteration can be considered the science of the future, taking into account the amount of research and analysis that has been carried out in recent years, with the willing and voluntary transformation of the genome, both human and animal.

The alteration of DNA, in most of its presentations, has as its sole purpose the conservation of the human species over the animal. An example of this is the most recent research carried out by Oxitec, a biotechnology firm based in Abingdon, United Kingdom, which, as Nature magazine explains in one of its articles, has managed to alter the DNA of the Aedes aegypti mosquito so that it is this himself the one who is in charge of his own destruction.

It should be remembered that this mosquito is responsible for the transmission of viruses such as chikungunya, dengue, zika and yellow fever, so ending the overpopulation of these insects has become a challenge and a necessity for science medical in the world.

What does this research consist of?

According to Nature, “the males designed by Oxitec carry a gene that is lethal to female offspring. If all goes according to plan, when released into the environment, the manipulated males should mate with wild females, and their female offspring will die before they can reproduce. The male offspring will carry the gene and pass it on to half of their offspring. As each generation mates, more females die and the A. aegypti population should decrease.”

To find out the effectiveness of this genetic modification, the researchers placed boxes with mosquito eggs and released them in a controlled space in the Florida Keys. Upon hatching, the altered males (which cannot sting) bred with the wild females, laying the first generation of eggs with the altered gene embedded in their DNA.

Thus, it was possible to find that the females that were born with the lethal gene died before reaching adulthood, while the males continued to reproduce. This effectiveness lasted about two or three generations of mosquitoes, that is, for two or three months.

Read also: What is pharmacogenomics and why is it considered the future of medicine?

What implications can it bring?

Of course, after the successful results in the Florida Keys and the authorization of the Environmental Protection Agency of the United States (EPA, for its acronym in English) to release more than 2 billion mosquitoes in California and Florida, it could be think that only good things can be expected from this research.

If this release works as expected, it would mean dealing a major blow to health programs that seek to counteract the spread of diseases transmitted by Aedes aegypti in the United States, in the first instance.

However, there is already a precedent carried out by Oxitec in Brazil, with an investigation that, although at first it killed 90% of the population of this insect in the city of Jacobina, in the region of Bahia, in the end it ended in a Complete failure when it was discovered that part of the wild mosquitoes adapted to the altered gene.

This led to exponential growth in mosquitoes, making them much more robust than the previous generation, according to a Yale research team that studied mosquitoes even 30 months after the release of the altered Aedes aegypti by Oxytec.

Although this result has not been glimpsed in the research carried out in the Florida Keys, the truth is that several experts have expressed fear that history will repeat itself and, instead of counteracting the health crisis, it ended up affecting it more.

However, there is also fear among the scientific community that genetic research with mosquitoes will end up seriously affecting other species of greater importance to the world's ecosystems, such as bees.

This has been explained by several experts, who criticize, especially an investigation by Imperial College London, in which it was possible to emit a genetic impulse (mechanism that forces the altered gene to be inherited by the total offspring of the same organism) that affects mainly the double-sex gene responsible for the sexual development of Anopheles gambiae, one of the mosquitoes responsible for malaria in Africa.

According to the research, the results of which were published in the journal Nature Biotechnology, it was possible to alter the double-sex gene so that, contrary to what was done by Oxitec, the females of these mosquitoes do not die but do lose all reproductive capacity, while that the males are in charge of transmitting the mutated gene among the wild females of a territory.

However, releasing these types of genetically modified insects could lead to an environmental catastrophe, since the genetic impulses that the mosquitoes would release cannot be easily disabled, nor reduced to a single territory.

For this reason, it is normal for the scientific community to fear that other species could be genetically driven to have flaws in their double-sex gene, and thus end them in the future.

Faced with this ethical, environmental and moral problem, Andrea Crisanti, leader of this research, gave a calm report by assuring that "this is not possible", since each species of insect has its own version of the double-sex gene, so According to Crisanti, the alteration of one species would not have to affect another totally different one.