genetic modification

• Gene to be inserted

  Located in the original organism
• Isolating the required gene

  1. Restriction enzymes used

  2. Leaves gene with 'sticky ends' (a short section of unpaired bases)
• Cutting a bacterial plasmid

  1. Same restriction enzyme used

  2. Leaves plasmid with corresponding sticky ends (plasmids are circles of DNA found inside bacterial cells)
• Joining the plasmid and isolated gene

  DNA ligase enzyme used
• If two pieces of DNA have matching sticky ends (because they have been cut by the same restriction enzyme), DNA ligase will link them to form a single, unbroken molecule of DNA
• Inserting the genetically engineered plasmid


  Into a bacterial cell