What is Cas9 protein that is often mentioned in news?
Contents15
- AA molecular scissors used in targeted gene editing
- BA biosensor used in the accurate detection of pathogens in patients
- CA gene that makes plants pest-resistant
- DA herbicidal substance synthesized in genetically modified crops
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Answer: (A) A molecular scissors used in targeted gene editing
The correct answer is (A) — a molecular scissors used in targeted gene editing.
Cas9 is a protein that is part of the CRISPR-Cas9 system — a revolutionary gene-editing tool borrowed from bacteria.
In nature, bacteria use CRISPR-Cas9 to cut and destroy viral DNA.
Scientists adapted this as a 'molecular scissors' to precisely cut, remove, or modify specific genes in any organism.
Tip:
CRISPR = the GPS that finds the gene,
Cas9 = the scissors that cuts it.
Cas9 is the 'molecular scissors' component of CRISPR-Cas9, the revolutionary gene-editing system that can precisely cut and modify DNA in any organism.
CRISPR-Cas9 was a major news topic around 2018-2019 due to the controversial gene-editing of human babies by Chinese scientist He Jiankui, making it highly relevant for UPSC.
The question tests understanding of what Cas9 specifically does versus other biotechnology applications like biosensors or GM crops.
Cas9 Protein & CRISPR System
Science And Technology Cas9 protein molecular scissors targeted gene editing
Cas9 Protein: The Molecular Scissors of Gene Editing
Cas9 is a protein that acts as molecular scissors in the CRISPR-Cas9 gene editing system
Originally a bacterial immune system, now adapted for precise gene editing in any organism
CRISPR guides Cas9 to the target gene, Cas9 cuts the DNA at that precise location
Won the 2020 Nobel Prize in Chemistry for Emmanuelle Charpentier and Jennifer Doudna
What is Cas9?
Cas9 (CRISPR-associated protein 9) is an enzyme that functions as molecular scissors in gene editing. It belongs to the CRISPR-Cas9 system — a tool that allows scientists to cut DNA at precise locations and modify genes with unprecedented accuracy.
How CRISPR-Cas9 Works
%%{init: {"flowchart": {"wrappingWidth": 460}}}%%
flowchart TD
s1["`**Guide RNA (gRNA) designed**
Scientists create a **guide RNA** that matches the target gene sequence`"]
s2["`**CRISPR finds target**
**CRISPR** system uses gRNA to locate the exact gene on DNA strand`"]
s3["`**Cas9 cuts DNA**
**Cas9 protein** acts as scissors and cuts both strands of DNA at target site`"]
s4["`**Gene modification**
Scientists can now **remove, replace, or insert** new genetic material`"]
s1 --> s2
s2 --> s3
s3 --> s4Natural vs Lab Use
Context | Purpose | Target | Outcome |
|---|---|---|---|
Natural (Bacteria) | Immune defense | Viral DNA invaders | Destroy virus DNA |
Laboratory | Gene editing tool | Specific genes in any organism | Modify/remove/add genes |
Applications & Potential
Medical: Treating genetic disorders like sickle cell anemia, muscular dystrophy
Agricultural: Creating disease-resistant crops, improving nutritional content
Research: Understanding gene function, creating disease models in lab animals
Future: Potential for treating cancer, HIV, and inherited diseases
CRISPR-Cas9 Mechanism
Source: World Ocean Review — How do CRISPR-Cas9 genetic scissors work? - World Ocean Review ... · worldoceanreview.com
Cas9 is the scissors, not the guide — CRISPR provides targeting, Cas9 does the cutting
Not a biosensor or detection tool — it's specifically for cutting and editing genes
Not a gene itself — it's a protein enzyme that cuts genes
Not herbicidal — it's a precision editing tool, not a broad-spectrum chemical
Gene Editing Techniques
Science And Technology targeted gene editing
Gene Editing Techniques: CRISPR and Beyond
CRISPR-Cas9 is the most advanced and precise gene editing technique available
Earlier techniques like ZFNs and TALENs were less precise and more expensive
Prime editing and Base editing are newer CRISPR variants for even more precision
Evolution of Gene Editing
Technique | Year Developed | Precision | Cost | Key Advantage |
|---|---|---|---|---|
Zinc Finger Nucleases (ZFNs) | 1996 | Moderate | High | First programmable nucleases |
TALENs | 2010 | Good | Moderate | Easier to design than ZFNs |
CRISPR-Cas9 | 2012 | Very High | Low | Simple, fast, versatile |
Prime Editing | 2019 | Extremely High | Low | No double-strand breaks needed |
Why CRISPR Won
Speed: Design and test new edits in days, not months
Cost: Dramatically cheaper than previous gene editing methods
Versatility: Works in plants, animals, bacteria, fungi — almost any organism
Precision: Can target specific DNA sequences with minimal off-target effects
Programmable: Just change the guide RNA to target different genes
Gene Editing Applications
# Gene Editing Applications
## Medical
- Cancer therapy
- Genetic disorders
- Organ transplants
- Drug development
## Agricultural
- Disease resistance
- Drought tolerance
- Enhanced nutrition
- Longer shelf life
## Research
- Disease models
- Gene function studies
- Biomarker discovery
## Industrial
- Biofuel production
- Pharmaceutical manufacturing
- Enzyme engineeringDon't confuse gene editing (precise modification) with genetic modification (broader term including traditional methods)
CRISPR is the targeting system, Cas9 is the cutting protein — they work together
Gene editing modifies existing genes — it doesn't create entirely new organisms from scratch
Biotechnology in India
Science And Technology
Biotechnology Applications & Regulation in India
Department of Biotechnology (DBT) under Ministry of Science & Technology promotes biotech research
GEAC (Genetic Engineering Appraisal Committee) regulates GM crops and organisms
India allows Bt Cotton but debates continue over Bt Brinjal and other GM crops
India's Biotech Landscape
India ranks among the top 12 biotechnology destinations globally. The National Biotechnology Development Strategy 2015-2020 aimed to establish India as a world-class bio-manufacturing hub with a $100 billion bioeconomy by 2025.
Key Indian Biotech Institutions
Institution | Role | Key Focus |
|---|---|---|
DBT (Department of Biotechnology) | Policy & funding | Research promotion, international cooperation |
GEAC | Regulatory approval | GM crops, biosafety assessment |
BIRAC | Startup support | Innovation funding, incubation |
ICMR | Medical research | Biomedical applications, clinical trials |
CSIR labs | Research | Drug discovery, industrial biotechnology |
Major Indian Biotech Achievements
COVID-19 vaccines: Covaxin (Bharat Biotech), Covishield (Serum Institute)
Insulin production: World's largest insulin manufacturer (Biocon)
Generic drugs: Leading supplier of affordable medicines globally
Agricultural biotech: Development of drought-resistant crop varieties
Biofuels: Research on algae-based and waste-to-energy solutions
GM Crops Status in India
# GM Crops in India
## Approved
- **Bt Cotton** (2002)
- Covers 95% of cotton area
## Under Debate
- **Bt Brinjal**
- **GM Mustard**
- Various field trials ongoing
## Concerns
- Farmer dependency
- Environmental impact
- Traditional varieties
## Benefits
- Pest resistance
- Higher yields
- Reduced pesticide useGEAC approves GM crops — not DBT or Ministry of Agriculture directly
India allows Bt Cotton but not Bt Brinjal (moratorium since 2010)
DBT is under Ministry of Science & Technology, not Health or Agriculture
Don't confuse BIRAC (biotech startup funding) with CSIR (research labs)