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Gene-Edited Sheep in India

Context

India’s first gene-edited sheep was developed by SKUAST-Kashmir using CRISPR-Cas9 technology, targeting the myostatin gene to enhance muscle mass by 30%. As no foreign DNA was introduced, the sheep is non-transgenic and aligns with India’s evolving biotech regulatory norms.

Institution Involved:

The research was carried out at SKUAST-Kashmir under the leadership of Riaz Ahmad Shah (Dean, Faculty of Veterinary Sciences).
SKUAST had previously cloned India’s first Pashmina goat (Noori) in 2012.

Technology Used:

CRISPR-Cas9, a gene-editing tool enabling precise DNA modifications, was used.
Adhered to international biosafety protocols, crucial for future regulatory clearance.

Scientific Basis:

The gene edited was myostatin, which naturally limits muscle growth.
Knockout (disruption) of this gene led to ~30% increased muscle mass—a trait seen in select European breeds like Texel, but absent in Indian sheep breeds.

Significance:

The gene-edited sheep does not contain foreign DNA, distinguishing it from transgenic organisms.
This makes it eligible for approval under India’s regulatory framework for gene editing, particularly under the 2022 notification of the Environment Protection Act (EPA), which exempts certain SDN-1 and SDN-2 gene-edited organisms from GMO classification.
This is considered a historic milestone in Indian livestock genetics and biotechnology.

Future Applications:

Creation of disease-resistant breeds.
Facilitation of twinning and reproduction efficiency.
Potential scaling in other livestock species.

Comparison to Recent Advances:

Follows India’s release of the first gene-edited rice variety supported by the Union Ministry of Agriculture.
Places India among global leaders in precision livestock breeding without transgenesis.

Ethical and Regulatory Relevance:

Being non-transgenic, such developments may encounter less public resistance and smoother regulatory approval.
Supports Make in India and Aatmanirbhar Bharat in biotechnology.

CRISPR Technology:

Definition and Origin

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats.
It is a gene editing technology inspired by a natural defense mechanism found in certain bacteria.
These bacteria use CRISPR-associated proteins (like Cas9) to cut and destroy viral DNA.

Key Components

Cas9 Protein: An enzyme that acts as molecular scissors to cut DNA at a specific location.
Guide RNA (gRNA): A synthetic RNA sequence that directs Cas9 to the targeted DNA segment.

Mechanism of Action

The CRISPR-Cas9 system identifies the faulty or unwanted DNA segment.
Cas9 makes a precise cut at the targeted location.
The DNA sequence can then be:
- Deleted,
- Corrected, or
- Replaced with a new sequence.
This process is often compared to “cut-copy-paste” or “find-replace” in computer operations.

Nature of Genetic Modification

Unlike traditional genetic engineering, CRISPR does not introduce foreign DNA.
The technique works by modifying existing genes, making the resulting organism non-transgenic.

Applications

Human Medicine: Correction of genetic disorders such as sickle cell disease or cancer mutations.
Agriculture:
- Development of disease-resistant or high-yield crops.
- Editing livestock genes (e.g., India's first gene-edited sheep targeting the myostatin gene).
Biotechnology: Creation of organisms with desired traits without foreign gene insertion.

PYQ:

With reference to the recent developments in science, which one of the following statements is not correct? (2020)

Functional chromosomes can be created by joining segments of DNA taken from cells of different species.
Pieces of artificial functional DNA can be created in laboratories.
A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory.
Cells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes.