CRISPR CAS9 TECHNOLOGY (Syllabus: GS Paper 3 – Sci and Tech)

Context: Researchers recently used CRISPR/Cas9 to alter photosynthesis for the first time.

CRISPR Cas9 Technology

• About: CRISPR is an acronym representing Clustered Regularly Interspaced Short Palindromic Repeats.
• It is an innovative technology that provides geneticists and medical researchers with the capability to alter precise segments of the genome.
• Discovery: Some bacteria possess a natural defense mechanism akin to CRISPR/Cas9, allowing them to target and disable viral DNA sequences by snipping them out and incorporating a part of it into their own genome for future immunity.
• Components

oCas9 Enzyme: Central to CRISPR/Cas9 is the Cas9 enzyme, likened to molecular scissors, capable of precisely cutting both strands of DNA at a predetermined location within the genome.

oGuide RNA (gRNA): Comprising a short pre-designed RNA sequence within a longer scaffold, the gRNA serves as a molecular guide, directing the Cas9 enzyme to the specific target site on the DNA.

• CRISPRs are unique segments of DNA with specialized functions.
• The protein Cas9, also known as "CRISPR-associated," functions as an enzyme resembling molecular scissors, proficient in cleaving DNA strands.
• This capability enables researchers to conveniently modify DNA sequences and manipulate gene behaviour.
• Mechanism of Action: The guide RNA is engineered to bind with high specificity to a particular sequence on the DNA, ensuring Cas9 cuts precisely at the intended genomic location.