Biotechnology gene cloning and Polymerase chain reaction

Gene cloning

• Isolates and creates copies of a gene
  • Useful for gene therapy
• 4 steps
  • Isolation
  • Ligation
  • Transformation
  • Selection

Isolation

• An enzyme is used to break DNA at a specific base sequence. This isolates the gene

Ligation

• The enzyme DNA ligase combines the isolated gene with plasmid DNA from bacteria
  • Plasmid DNA is circular DNA that is not part of a chromosome and can replicate independently
• The resulting DNA is called @@Recombinant DNA@@

Transformation

• The recombinant DNA is inserted into a living cell (usually bacteria)
  • This change is also called @@genetic engineering@@

Selection

• Growing transformed bacteria to ensure they have the recombinant DNA
• Important as transformation is not always successful

Polymerase chain reaction (PCR)

• Creates copies of a gene or other DNA segment
• Used to make large quantities of a gene for genetic testing
• 3 Steps
  • Denaturing
  • Annealing
  • Extention

Denaturing

• Heating DNA to break the bond holding the 2 DNA strands together
• Creates 2 single DNA strands

Annealing

• Cooling the single strands and mixing them with short DNA segments called primers
• Primers have sequences complementary to segments on the single DNA strand
• Bond forms between strands and primer

Extention

• An enzyme adds nucleotides to the primers
• This creates new DNA molecules each incorporating one of the original DNA strands