Genetic engineering gives mosquito control an upgrade
Science & Technology
14th Sep, 2023
The surge in mosquito-borne diseases due to urbanization and climate change calls for innovative mosquito control approaches. Sequencing and genetic manipulation of mosquito genomes offer promising tools for effective disease prevention.
What is gene drive?
- Scientists worldwide have developed various genetic modification approaches. A major one in this endeavour is gene-drive technology, whose end result is for mosquitoes to selectively inherit some genes, rather than the inheritance to follow the rules of Mendelian genetics.
- A gene drive is a type of genetic engineering technique that modifies genes so that they don’t follow the typical rules of heredity.
- Gene drives dramatically increase the likelihood that a particular suite of genes will be passed onto the next generation, allowing the genes to rapidly spread through a population and override natural selection.
- This technology was conceived by Austin Burt, professor at Imperial College London, in a 2003 paper published in Royal Society Proceedings.
How does it work?
- Gene drives work by using directed repair gene editing.
- This enables the insertion of a new gene, called the driven gene, at a particular cut site through the use of a donor template.
- It would lead to prevention of diseases.
- It can help to address the challenges of invasive species.
- Drastic reduction in the mosquito population could alter food chains and ecosystems that involve mosquitoes.
- Unintended consequences can occur such as unforeseen ecological disruptions
- Potential for engineered genes to spread beyond target mosquito populations.
How GM mosquitoes are produced and used to control Ae. aegypti mosquitoes?
- GM mosquitoes are mass-produced in a laboratory to carry two types of genes
- A self-limiting gene that prevents female mosquito offspring from surviving to adulthood.
- A fluorescent marker gene that glows under a special red light. This allows researchers to identify GM mosquitoes in the wild.
- GM mosquitoes produced in the laboratory lay eggs. These eggs carry the self-limiting and fluorescent marker genes.
- GM mosquito eggs that carry the self-limiting gene are released into an area. Once they have hatched and develop through to the adult stage, they are available to mate with wild females. The genes are passed on to offspring
- The female offspring die before they become adults. The expected result is that the number of Ae. aegypti mosquitoes in the area decreases.
Effectiveness of GM mosquitoes in reducing numbers of mosquitoes
- GM mosquitoes have been successfully used in parts of Brazil, the Cayman Islands, Panama, and India to control Ae. aegypti mosquitoes. Since 2019, over 1 billion mosquitoes have been released.
- When GM mosquitoes stop being released into an area, the Ae. aegypti mosquito population will slowly return to “normal levels.”
- GM mosquitoes will only work to reduce numbers of target mosquito species (e.g., Ae. aegypti), not other types of mosquitoes. Most communities have more than one type of mosquito.