Context:
Researchers at Sher-e-Kashmir University of Agricultural Sciences and Technology (SKUAST), Srinagar, have recently developed India’s first gene-edited sheep, marking a significant advancement in livestock genetics after four years of research.
Key Achievements:
- The gene-editing focused on the myostatin gene, which regulates muscle growth in sheep.
- The gene-edited sheep of the local ‘merino’ breed weighed almost the same as a normal lamb at birth, but within three months, it became at least 100 grams heavier than a non-edited lamb.
- This modification increased muscle mass by about 30%, a trait naturally missing in Indian sheep breeds but present in some European breeds like the Texel.
- The gene-editing was performed using CRISPR-Cas9 technology, a precise tool recognized globally and awarded the Nobel Prize in Chemistry in 2020.
- The edited sheep does not contain any foreign DNA, distinguishing it from transgenic organisms and potentially easing regulatory approval under India’s evolving biotech policies.
Gene editing and CRISPR Technology:
Gene editing, also known as genome editing, is a group of technologies that allow scientists to precisely change an organism's DNA. These technologies enable the addition, removal, or alteration of genetic material at specific locations within the genome.
About CRISPR:
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. It is a gene-editing tool inspired by a natural defense mechanism found in certain bacteria. These bacteria use CRISPR-associated proteins, such as Cas9, to cut up and destroy viral DNA.
Key Components:
· Cas9 Protein: Acts like molecular scissors that cut DNA at a specific site.
· Guide RNA (gRNA): A custom-designed RNA sequence that tells Cas9 exactly where to cut in the DNA.
How It Works:
1. The guide RNA identifies a specific segment of DNA—usually faulty or unwanted.
2. Cas9 cuts the DNA at this targeted location.
3. Scientists can then:
o Delete the gene,
o Correct it, or
o Replace it with a new sequence.
This process is often compared to "cut-copy-paste" or "find-replace" operations used in computers. Importantly, CRISPR does not introduce foreign DNA. Instead, it works by modifying the organism’s existing genes, making the result non-transgenic and potentially more acceptable to regulators and consumers.
Potential Applications:
Gene-editing in livestock offers several benefits, including:
- Creating disease-resistant animals by targeting genes linked to illness.
- Enhancing reproductive traits such as twinning in births.
- Improving important productivity traits efficiently without traditional crossbreeding, thus accelerating genetic improvement.
This development follows earlier success in producing a gene-edited buffalo embryo at the National Dairy Research Institute, signaling a new era in Indian livestock biotechnology.
