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- Typos and Scotch Tape
- Designing Crops for a Changing Climate
- What does gene editing look like today?
- Coral Conservation: The Tides are Changing
- The Era of Editing
- Crop Biotechnology: Fear, not Foe
- Typos and Scotch Tape
- Gene Editing: Not as Scary as it Sounds
- A cutting-edge approach to an ancient problem: gene editing takes a bite out of malaria
- Genome Editing - The Future of Our Food?
- Break and repair - What do they really mean by gene "editing"?
- Take the Guessing out of Gene Editing
- Preventing Malaria with Genetic Engineering
Preventing Malaria with Genetic Engineering
by Samantha Connolly
Each year, hundreds of thousands of people die from malaria and millions more suffer. We have intervened in the spread of malaria by using insecticides to control mosquito populations. However, mosquitos have begun to evolve resistance to the insecticides. What will happen when the insecticides no longer effectively keep mosquito population levels down? Scientists have proposed a “gene drive” to combat the spread of malaria.
Plasmodium parasites cause malaria. These parasites reside in female Anopheles
The doublesex gene
Genes are encoded by DNA, and mosquitoes have two copies of every gene. Enzymes determine where the genes are in the DNA and create a molecule called messenger RNA (mRNA) based on the DNA’s sequence. This process is known as transcription. The enzyme can read the DNA in several different ways, and therefore can create different mRNA molecules from the same DNA sequence.
This is exactly what happens for the doublesex gene in mosquitoes. In females, the mRNA transcript of the doublesex gene contains a piece that is not present in the male mRNA transcript. This means that the same sequence of DNA is transcribed differently in female and male mosquitoes.
Using a genetic engineering tool called CRISPR-Cas9, scientists are able to modify the sequence of the DNA right next to the particular part of the doublesex gene that is transcribed differently in females and males. This means that when males have this modified gene, their mRNA is totally normal, and therefore the males are normal. But when females have this modified gene, their mRNA is abnormal. When females have two copies of the modified doublesex gene, they are unable to lay eggs and cannot bite.
If a male Anopheles mosquito with the mutated doublesex gene mates with a female Anopheles mosquito, their offspring will contain the mutated doublesexgene. If many genetically engineered male mosquitoes were released into the environment, they would mate with the female mosquitoes in the environment and the gene would “drive” its way through the mosquito population. Because females with two copies of the gene are unable to lay eggs, the mosquito population would collapse. This was tested on caged mosquitoes: within 7-11 generations, the mosquito population successfully crashed due to the gene drive.
More research is needed into the effects of using this genetic engineering technology outside of a laboratory setting. However, genetically engineering mosquitoes to prevent malaria is an exciting prospect and demonstrates the power of genetic engineering to help humanity.