S u m m a r y :
A wingless, three-eyed mosquito has been genetically engineered by a team of researchers in an attempt to curb the propagation of infectious diseases. The findings are published in the Proceedings of the National Academy of Sciences.
You now have three-eyed, wingless mosquitoes, thanks to genetic engineering. A team of researchers from the University of California, Riverside, has sought to modify a species of mosquitoes called Aedes aegypti—which are carriers for the pathogens behind diseases like dengue, chikungunya, yellow fever, zika—in an effort to ultimately hinder the insects from spreading the infections.
Creating 3-Eyes, Wingless Mosquitoes
Led by Omar Akbari, the scientists added the gene for a bacterial enzyme known as Cas9 so that they could use a gene editing tool known as CRISPR to make specific modifications in the DNA of the mosquitoes; CRISPR identifies and cuts out specific DNA sequences, replacing them using an RNA guide. As proof of concept, Akbari and his colleagues genetically disrupted genes that control vision, flight, and feeding such that the development of wings, eyes, and cuticle in the insects was changed. They, thus, successfully created yellow, three-eyed, and wingless mosquitoes. The end-goal is to use a gene technology called gene drives on mosquitoes which express Cas9 to insert genes suppressing the insects while also preventing them from developing resistance against the new traits that would put them at a disadvantage. It is to be noted that these disease-carrying mosquitoes are becoming increasingly resistant to pesticides.
Curbing Spread of Diseases
According to Akbari, their research marks the first step to building gene drive systems to monitor mosquito populations with the aim of curbing diseases related to them.
“These Cas9 strains can be used to develop split-gene drives which are a form of gene-drive by which the Cas9 and the guide RNA’s are inserted at separate genomic loci and depend on each other for spread. This is the safest way to develop and test gene drives in the laboratory to ensure no spread into the wild,” says Akbari.
Destroying Mosquitoes with Genes
Gene drives increase the likelihood of genes to be passed down to offspring from 50% to 99%. These systems are used to bias the genetic inheritance to give the advantage to self-destructive genes; according to the authors, this system could constitute an environmentally friendly, and cost-effective strategy to get rid of disease-carrying insects.
“Next steps should be undertaken to identify the regulatory sequences that can be used to express the guide RNAs from the genome, and once these sequences are identified developing gene drives in the species should be turnkey,” says Akbari.