‘This CRISPR/Cas9 method overcomes previous difficulties and opens up a whole new avenue for scientists to generate genetic pest management strategies…’
Researchers at the Pirbright Institute have used the CRISPR/Cas9 gene editing tool to introduce a gene for a fluorescent protein into the genome of southern house mosquitoes (Culex quinquefasciatus Say). The gene could be passed on to the next generation through mating. The researchers say that this development ‘paves the way for genetic control methods that could prevent the mosquito from spreading human and animal diseases.’ The work has been published in the journal Scientific Reports.
The female southern house mosquito feeds largely on birds, leading to the transmission of avian malaria, which is said to have played a role in the extinction of several avian species. In addition, the mosquito targets mammals spreading diseases such as lymphatic filariasis. There are 50 million human cases of this disease worldwide, despite mass drug administration programmes. Current control methods for the southern house mosquito involve insecticides, which pose hazards for human and ecosystem health, while also becoming increasingly ineffective with the rise of resistance.
The researchers say that advances in genome editing have allowed the development of genetic insect control methods which are species-specific. The Pirbright researchers inserted a gene producing red fluorescence proteins so the mosquitoes with one or more edited gene fluoresce red.
An eye colour gene was targeted for the insertion of the fluorescence gene, so that mosquitoes inheriting two edited genes from their parents would have white eyes, not black. Researchers said that these traits make it easier to identify those mosquitoes where the genome has been modified. The researchers added that although the specific eye colour gene would not be targeted for creating any functional genetic pest management tools, it has provided proof that the method can work in this species.
Professor Luke Alphey, head of the Arthropod Genetics Group at Pirbright said: ‘This CRISPR/Cas9 method overcomes previous difficulties, and opens up a whole new avenue for scientists to generate genetic pest management strategies. This could ultimately prevent millions of people and animals from falling ill because of this invasive mosquito species.’
During August, researchers in Australia started a three year project using genomic sequencing to develop strategies to suppress the Aedes vigilax mosquito, which spreads the Ross River virus.