It’s a bacterial defence mechanism against virus.
• CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)
• Cas9 (CRISPR-associated protein 9) = Scissors (Cut virus genome)
C - Clustered
R - Regularly
l - Interspaced (add spacers)
S - Short
P - Palindromic
R - Repeats
CRISPR-Cas9 Mechanism-
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Steps |
CRISPR-Cas9 Mechanism |
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1. Viral Infection |
A virus attacks a bacterium and injects its DNA. |
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2. Bacterial |
The bacterium cuts and stores a small piece of the viral DNA into its own genome at the CRISPR region (acts like a genetic memory). |
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3. Spacer Addition |
These viral DNA pieces (called spacers) help the bacterium recognize the same virus in the future. |
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4. Second Attack |
If the same virus infects again, the bacterium uses the stored sequence to make guide RNA. |
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5. Target & Destroy |
The guide RNA teams up with the Cas9 enzyme (a DNA-cutting protein) and finds the matching viral DNA — then Cas9 cuts it, disabling the virus. |
Feluda test:
- for Covid 19
- based on CRISPER-Cas9