Genetic Engineering and Insulin Production

Historical Context

• Past Insulin Sources:
  • Diabetics previously used insulin from cows or pigs.
  • Issues with compatibility and effectiveness.

Modern Insulin Production

• Current Source:
  • Insulin is now produced by microorganisms like E. coli and yeast.

Genetic Engineering Overview

• Definition:
  • Manipulation or alteration of an organism's DNA.
• Genes and Proteins:
  • DNA contains genes coding for proteins necessary for survival.
  • Each gene codes for a specific protein or part thereof.

Process of Genetic Engineering

• Transgenic Organisms:
  • Removal of a gene from a donor organism and transfer to a recipient.
  • Recipient becomes a transgenic or genetically modified organism.
• Purposes:
  • Produce large volumes of proteins (e.g., insulin, growth hormone, vaccines).
  • Provide organisms with advantageous traits (e.g., pest resistance in plants).

Example: Insulin Production Process

1. Gene Identification and Extraction:
   • Insulin gene located on human chromosome 11, position 15.5.
   • Cut from the chromosome using restriction enzymes.
2. Plasmid Preparation:
   • Bacterium plasmids: small circular DNA in cytoplasm.
   • Extract and cut open a plasmid using the same restriction enzymes.
   • Sticky ends allow for complementary base pairing.
3. Gene Insertion:
   • Insulin gene inserted into bacterial plasmid via sticky ends.
   • Ligase enzyme completes the DNA joining.
4. Transformation:
   • Insert modified plasmid back into bacterial cell.
   • Resulting bacterium is transgenic with recombinant DNA.
5. Replication and Expression:
   • Bacteria in fermenter reproduce asexually as clones.
   • Express both their own genes and human insulin gene.
6. Extraction and Purification:
   • Human insulin is extracted, purified, and packaged for use.

Conclusion

• Genetic engineering transforms microorganisms into factories producing human insulin.
• Allows diabetics to use human insulin instead of less ideal animal insulin.