Animation 27.1 Basic principle of recombinant DNA technology

Main ideas / concepts

• Recombinant DNA technology is a technique used to transfer a DNA fragment (containing a gene) from one organism (donor) into the DNA of another organism (host).
• The purpose is to introduce a new characteristic into the host by inserting a new gene.
• The process results in a recombinant plasmid that can be put into a host cell to achieve outcomes such as:
  • Producing proteins from other species (example: human insulin)
  • Creating genetically modified organisms with new traits/characteristics

Methodology: the four major steps

1. Obtain the gene-containing DNA fragment

   • Isolate a DNA fragment from the donor cell that contains the gene of interest.

2. Obtain a suitable plasmid (vector)

   • Isolate a plasmid from a bacterium.
   • Plasmids commonly function as vectors—vehicles used to carry the gene of interest into a host cell so the gene can be expressed.

3. Cut both the gene fragment and the plasmid with a restriction enzyme

   • Use a restriction enzyme (described as “scissors”).
   • This enzyme:
     • Recognizes a specific base sequence
     • Cuts DNA at a specific point
   • The same restriction enzyme is used to:
     • Cut open the plasmid
     • Cut the DNA fragment containing the gene of interest

4. Join the gene fragment into the plasmid using DNA ligase

   • Use DNA ligase (described as “glue”).
   • DNA ligase catalyzes the joining of the cut DNA fragment to the cut plasmid.
   • This produces a recombinant plasmid.

Final application

• The recombinant plasmid is then introduced into a host cell to:
  • Enable production of proteins from other species (example: human insulin)
  • Create genetically modified organisms with new characteristics

Speakers / sources featured

• No specific speakers or named sources are mentioned in the subtitles (only background “[Music]” is indicated).