CRISPR and GMO

CRISPR-Cas9

  • Gene Editing Technology: Allows changes to DNA, specifically for repairing faulty genes without replacing them.
  • Advantages Over Traditional Gene Therapy:
  • Precise targeting of faulty genes.
  • Reduces risk of harmful mutations from incorrect gene insertion.

Process of CRISPR-Cas9

  1. Cas-9 Nuclease Addition: Introduces the enzyme to the target cell.
  2. Guide RNA (gRNA): Single-stranded gRNA directs Cas-9 to the specific DNA sequence.
  3. DNA Unwinding: Cas-9 unwinds the target DNA.
  4. Cutting DNA: Cas-9 cuts both strands of DNA just upstream of the PAM sequence.

Types of Gene Editing with CRISPR-Cas9

  • Gene 'Knock-in': Inserting a new DNA segment to fix a faulty gene.
  • Example: Replacing missing DNA bases in a defective gene to restore function.
  • Gene 'Knock-out': Silencing a gene by introducing mutations.
  • Example: Deleting bases to create a frameshift mutation, rendering the gene non-functional.

Genetically Modified Organisms (GMOs)

  • Definition: Organisms whose genomes have been modified, including animals and plants.
  • Transgenic Organisms: A subgroup of GMOs with DNA from different species added to their genome.

Examples of GMOs

  • Animals:

  • Super-Sized Mouse: Human growth hormone gene for faster growth.

  • GloFish: Fluorescent protein from sea anemone makes fish glow.

  • Silk-Spinning Goat: Spider silk production gene allows milk to contain spider silk protein.

  • Plants:

  • Cotton: Gene for insecticide protein increases pest resistance.

  • Papaya: Virus resistance gene inserted into papaya seeds.

  • Golden Rice: Genes for beta-carotene production help combat vitamin A deficiency.

Key Takeaways

  • All transgenic organisms are GMOs, but not all GMOs are transgenic.
  • CRISPR-Cas9 enhances genetic editing precision with significant potential in medical and agricultural biotechnology.