Genetic Fingerprinting

• Genetic fingerprinting


  A technique used to compare 2 DNA samples & determine whether they came from the same individual
• Organism's genome


  • Contains non-coding regions - variable number tandem repeats (VNTRs)
  • Probability of 2 individuals having the same VNTRs is very low, so we can compare these areas to see if 2 DNA samples came from the same person
• Genetic fingerprinting analysis


  1. DNA sample obtained

  2. VNTRs cut out using restriction enzymes

  3. Labelled

  4. Cloned using PCR

  5. Fragments separated using gel electrophoresis

  6. Banding patterns of each sample can then be compared
• Gel electrophoresis


  • DNA fragments are placed at one end of a slab of gel
  • An electric current is applied, causing the DNA fragments to move towards the other end of the gel
  • Shorter fragments travel further
  • The pattern of bands created is unique to every individual
• Applications of genetic fingerprinting


  • Forensics e.g. to identify victims or suspects
  • Medical diagnosis e.g. to identify the type of haemoglobin produced by an individual to diagnose sickle cell anaemia
  • Animal & plant breeding e.g. breed out harmful alleles, ensure pedigree