Non-malarial mosquitoes

<url> 

A group of scientists used modern genome editing methods to create malaria mosquitoes in whose body plasmodium, the causative agent of malaria, cannot develop (Elizabeth Pennisi, Science: Gene drive turns insects into malaria fighters). If further developed, this method will become a new and possibly the most effective way to eradicate malaria.

Anthony James from the University of California at Irvine started working on this problem 20 years ago. In 2012, he was able to isolate from the mouse genome a gene responsible for antibodies to malaria, which makes rodents immune to human malaria. The gene was able to be embedded in the genome of one of the species of malaria mosquitoes, and, as the experiment showed, the malaria plasmodium, once in the mosquito's body, died. But Anthony James did not have a method that would allow editing the genome of thousands of mosquitoes in nature.

Ethan Bier came to the rescue, whose laboratory at the University of California, San Diego, is engaged in editing the genome of drosophila flies using the CRISPR-Cas9 method (you can read more about it in the essays "Genome Editing: pros and cons" and "A new step in genome editing"). Bir came to the conclusion that this method will help solve the problem with malaria mosquitoes.

It was necessary to perform a difficult task: to introduce into the genome of a mosquito a huge fragment of DNA with a size of 17 thousand bases, so that at the same time it would remain active. Experiments were conducted on males and females of the species Anopheles stephensi. To test the heritability of the desired gene, scientists linked it with the gene that determines the color of the mosquito's eyes. As a result, all mosquitoes that inherited the transplanted gene had light eyes.

The technology proved to be effective, and 99% of the offspring of transgenic mosquitoes received the desired gene from their parents. The gene was active in the insect's body, providing a reliable barrier against malaria plasmodium. Calculations show that in 10 generations of mosquitoes, the gene will spread throughout the population.

However, the researchers faced a number of problems. The gene does not work in female malaria mosquitoes. In addition, the Cas9 protein used for genome editing turned out to be toxic to mosquitoes, and it had to be slightly modified. But the researchers are confident that, in general, the strategy they have chosen will work.

Now it is necessary to check the possible environmental effects of this intervention in the genome, as well as to make sure that the changes remain stable for many generations of mosquitoes. Also, the development of national and international standards for the use of genetically modified mosquitoes in nature is still ahead.

The work of scientists is described in the journal Proceedings of the National Academy of Sciences (Gantz et al., Highly efficient Cas9-mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi).

Portal "Eternal youth" http://vechnayamolodost.ru

24.11.2015