Malaria kills over a million people each year, taking child and adult victims. Although nets and insecticides have become common defenses against the mosquitoes spreading this disease, scientists have been working to develop a more aggressive technique in the fight against malaria.

Through research by a group at Imperial College London, scientists are exploring an approach that involves injecting male mosquitoes with a gene that will cause their offspring to most often turn out to be male. The method involves injecting the males with a homing endonuclease called I-PpoI, which will attach itself to a part of the X chromosome. When the males make sperm, the gene destroys part of the chromosome, making it more likely for the parents to produce male offspring. Data from their trials suggests 95 percent of the offspring were fertile males who were able to pass on this gene to their offspring, which, in turn, passed it on to their offspring.

Because they do not bite humans, one immediate advantage to this method is that males don’t transmit the disease. If successful, the hope is that this technique will eventually result in a severe drop in the mosquito population, and perhaps in the future it will result in their complete annihilation. In 2008, a group worked to fight the disease with a similar idea, and while their efforts yielded sterile mosquitoes, the inability to pass on the injecting gene proved unhelpful in the larger battle to eradicate malaria. Although the notion of toying with the sexes of mosquitoes in order to combat malaria was considered about 50 years ago by evolutionary biologist Bill Hamilton, the technology to do so has not been available until very recently.

In an interview with The Guardian, a lecturer at the London School of Hygiene and Tropical Medicine expressed concern with the mating patterns of mosquitoes. He said while there was no concrete evidence to prove they would not, he wondered how often the wild females would mate with the transgenic males instead of the wild males. Overall, however, he noted that the proposed project possessed much promise.

Director of GeneWatch UK Dr. Helen Williams relayed her concern to The Guardian in a different respect. Williams said that before implementing this technique as the main method against malaria-causing mosquitoes, scientists will need to consider the environmental impacts of their decision. While this technology provides a great potential for the disappearance of malaria, analyzing how other factors of the environment will be affected should also be of chief concern.

— Jordyn Horowitz

Sources: World Health Organization, NetsForLife, The Guardian, PLOS Genetics
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