Context:
Gene drive technology has been used in outdoor trials in India, Brazil, and Panama to genetically manipulate mosquitoes.
Scientists have harnessed genome sequencing and CRISPR-based genetic engineering to control mosquito populations by accessing the entire genome sequences of various mosquito species.
About Gene-drive technology:
- A type of genetic engineering technique that modifies genes and selectively inherits certain genes.
- It does not follow Mendelian inheritance rule.
- Mendelian inheritance rule refers to certain patterns of how traits are passed from parents to offspring.
- Working –
- Introduction of a genetic adjustment in the population of a species by altering the rules of inheritance from parent to offspring.
- A gene called ‘doublesex’ in female mosquitoes is disrupted using the CRISPR gene editing tool.
- The female mosquitoes inherit 2 copies of the disrupted gene.
- They develop like males and are unable to bite or lay eggs thus cannot transmit malaria-causing parasites from their bodies to humans.
- Significance –
- It can be used to exterminate insects such as mosquitoes that can spread malaria, dengue, and Zika virus.
- Used to control invasive species like rodents.
Do You Know?
Only female mosquitoes bite. They need a blood meal to produce eggs.
Male mosquitoes do not bite. They feed on nectar from flowers.
About Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas 9:
- CRISPR is a genetic code or sequence found in bacteria.
- Formed due to the activity of the previous bacteriophages that had infected them.
- Bacteria use CRISPR sequence to remember each specific virus that attacks them by incorporating virus DNA into their own bacterial genome.
- It gives the bacteria protection when a specific virus tries to attack again.
- What is CRISPR-associated protein 9 (Cas9)?
- A bacterial RNA-guided endonuclease that once activated will make special enzymes that seem to have coevolved with CRISPR.
- 3 key elements of CRISPR-Cas9 –
- Guide RNA: A piece of RNA that locates the targeted gene (It is engineered in a lab)
- Cas9: The “scissors” that snip the undesired DNA out.
- DNA: The desired piece of DNA that is inserted after the break.
With other forms of genetic engineering, the altered gene follows normal rules of inheritance and is passed on to only 50% of the offspring. Gene drives can paste themselves into a gene inherited from an unaltered, ensuring the genetic change gets more often.
Click here to read about Wolbachia method
Source: The Hindu
Previous Year Question
‘Wolbachia method’ is sometimes talked about with reference to which one of the following?
[UPSC Civil Services Exam – 2023 Prelims]
(a) Controlling the viral diseases spread by mosquitoes
(b) Converting crop residues into packing material
(c) Producing biodegradable plastics
(d) Producing biochar from thermo-chemical conversion of biomass
Answer: (a)
