The latest news highlights an innovative system created by researchers, designed to control mosquito populations using cutting-edge Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based genetic engineering. The importance of this development lies in the fact that mosquitoes are known vectors for serious diseases like dengue and malaria, which affect millions of individuals globally each year.
Understanding the Sterile Insect Technique (SIT) and its Progression
One of the main features of the new system is the application of the Sterile Insect Technique (SIT). SIT is an environmentally-friendly method, which has already proven its effectiveness in suppressing wild mosquito populations. To enhance its utility, scientists have integrated a novel CRISPR-based technology called precision-guided Sterile Insect Technique (pgSIT).
Exploring the pgSIT Technique
pgSIT represents a new, scalable genetic control system that uses a CRISPR-based methodology to engineer deployable mosquitoes that can then suppress their own populations in the wild. Unlike female mosquitoes, males do not transmit diseases, so the focus of this strategy is to produce and release increasing numbers of sterile male mosquitoes. This approach offers an effective way to limit mosquito populations without resorting to harmful chemicals or insecticides.
The pgSIT mechanism targets genes associated with male fertility—resulting in the creation of sterile offspring—and genes affecting female flight in the Aedes aegypti species. This particular species is known for spreading diseases including dengue fever, chikungunya, and Zika. The dominant genetic component of pgSIT enables simultaneous sexing and sterilization. By releasing eggs into the environment, only sterile adult males emerge, allowing for safe and controlled population management.
Another advantage of the pgSIT technique is its self-limiting nature, meaning it does not persist or spread uncontrollably within the environment. This, along with its other safety features should contribute to increased acceptance and application of this technology.
Potential Applications and Implications
pgSIT eggs can be either shipped to areas threatened by mosquito-borne disease or produced at a local facility for immediate deployment. Once released into the wild, sterile pgSIT males will mate with females, effectively reducing the wild population as required.
CRISPR: The Backbone of the Technology
The CRISPR gene-editing technology is a key element of this system. Inspired by natural defense mechanisms found in bacteria, CRISPR uses a specialized protein – Cas9 – to essentially cut and paste segments of DNA containing genetic information.
In the process, the specific location of genetic codes needing alteration is identified on the DNA strand. The Cas9 protein then acts like a pair of scissors to cut this location from the strand. As broken DNA tends to repair itself naturally, scientists intervene during this auto-repair stage, supplying the desired sequence of genetic codes that then bind with the broken DNA strand.
The simple yet precise nature of CRISPR-Cas9 technology holds immense potential to revolutionize many aspects of human life in the future. In recognition of this, Emmanuelle Charpentier from France and Jennifer A Doudna from the USA were awarded the 2020 Nobel Prize in Chemistry for their development of the CRISPR/Cas9 genetic scissors.