1. Recombinant DNA technology – combining genes from different sources into a single molecule. The result is a transgenic organism
Bacteria, like E coli, readily host
recombined DNA
Transgenic food crops are modified for pest resistance and increased nutrition

2. Plasmids – extrachromosomal DNA - are used
to customize bacteria

3. Bacterial plasmids are copied during binary fission so they function well as vectors for inserting/copying gene DNA

5. Restriction enzymes ‘cut and paste’ DNA
• Used by bacteria to
cut up foreign DNA
• Each recognizes a
specific DNA sequence
• Many are pallindromes
Blunt cuts
Staggered cuts

6. Restriction enzymes (endonucleases) that produce
staggered cuts are used for recombining DNA
The staggered cuts create ‘sticky ends’ that easily base pair

7. Using the same restriction enzyme on DNA from multiple
sources produces
complementary sticky ends
Ligase brings together the
sugars & phosphates of the
two nucleic acids

8. restriction enzyme, the plasmid and gene base-pair
Cut with the same
restriction enzyme, the
plasmid and gene base-pair
to make recombinant DNA
Application: producing
gene products, i.e. HGH

9. Recombinant DNA
overview

10. Cloning genes in plasmids
Recombinant plasmid
Bacterium takes up plasmid
Bacteria are allowed to divide
forming a colony of clones
Test each colony with antibiotics

11. Look for the colonies that took up the target gene(s)

12. GFP in
Aequorea victoria

14. How to identify the clones with the gene of interest?
• pair the gene with another for antibiotic
resistance; test each clone group using antibiotics
• If the gene of interest produces a protein,
like HGH, see which clones can
• Use a nucleic acid probe – create the base sequence that complements
the inserted gene. Tag it with florescence or radioactivity. Mix with heated
DNA to get visual confirmation