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Sunday, September 13, 2026

Altering DNA (CRISPR)

The primary and most widely used method for altering DNA is CRISPR gene editing, a precise technology that functions like a molecular "find and replace" tool for the genetic code. [1, 2]

 

How CRISPR Works

 

  • Guide RNA: Scientists program a short piece of RNA with the exact "address" or sequence of the target DNA they want to change.
  • Cas9 Enzyme: This protein acts as molecular scissors to attach to the target site and cut through the DNA strands.
  • Cellular Repair: The cell detects the broken DNA and triggers its natural repair process to fix the gap. [1, 2, 3, 4]

 

Types of DNA Repair and Modification

 

  • Disruption (NHEJ): The cell mends the cut without a template, often introducing a small deletion that turns a faulty gene off.
  • Insertion or Correction (HDR): Scientists supply a new DNA template alongside the scissors, allowing the cell to copy and paste a healthy sequence into the genome.
  • Base Editing: A newer variation chemically changes one single DNA letter to another without cutting the double-stranded helix. [1, 2, 3, 4]

 

Other Methods

 

  • Older Nucleases: Tools like Zinc Finger Nucleases (ZFNs) and TALENs were used before CRISPR to make targeted cuts, though they are harder to design and more expensive.
  • Viral Vectors: Viruses are often modified and used as delivery trucks to carry healthy genes into human cells during gene therapy. [1, 2]

 

Source and references:

AI Google

Genome editing - Wikipedia

https://www.youtube.com/watch?v=XPDb8tqgfjY&t=1

https://www.youtube.com/watch?v=2pp17E4E-O8&t=10

 

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