Key Terms & Concepts — UPSC Mains
Genome Editing (CRISPR-Cas9)
"A precise molecular tool that edits an organism's own DNA at targeted sites without necessarily inserting foreign genes"
Genome editing is a group of technologies that allow scientists to change an organism's DNA at precise locations by adding, removing or altering genetic material. CRISPR-Cas9, the most widely used system, uses a guide RNA to direct the Cas9 enzyme to a specific DNA sequence, where it makes a cut that the cell then repairs, producing the desired edit. When no foreign DNA is introduced (categories SDN-1 and SDN-2), the product is often not classified as a genetically modified organism, which eases regulation. The technology has applications in agriculture, medicine and industrial biology.
High relevance for GS3 (biotechnology, food security, health, IPR and ethics). India became the first country in the world to release genome-edited rice varieties in 2025, using CRISPR to raise yields and stress tolerance without foreign genes. This makes genome editing a live topic for Prelims (SDN categories, Cas9) and Mains (biosafety, ethics, agricultural self-reliance).
- 1 CRISPR-Cas9 uses a guide RNA and the Cas9 enzyme to cut DNA at a precise target site
- 2 SDN-1 and SDN-2 edits introduce no foreign DNA and are exempt from India's stricter GMO rules
- 3 [object Object]
- 4 India was the first country in the world to release genome-edited rice, with reported yield gains up to 19% and earlier maturity
- 5 The Ministry of Environment cleared SDN-1 and SDN-2 from the ambit of GMO regulations
- 6 The 2020 Nobel Prize in Chemistry went to Emmanuelle Charpentier and Jennifer Doudna for CRISPR-Cas9
- 7 Ethical concerns focus on germline editing of humans and unintended off-target effects
In 2025 India became the first country in the world to release CRISPR genome-edited rice, with Pusa DST Rice 1 and the DRR Dhan 100 (Kamala) variety showing higher yields and better drought tolerance without any foreign DNA.
