Genetic fingerprinting

• Describe how to identify individuals using genetic fingerprinting

  • The non-coding base sequences between genes are called VNTRs (variable number tandem repeats)
  • Each person has a different number of VNTRs between each of their genes
  • So each person produces a unique pattern of DNA fragments when their DNA is cut using restriction endonucleases
• Describe the process of genetic fingerprinting

  1. DNA is amplified using PCR
  2. DNA is cut next to the VNTRs using restriction endonucleases
  3. DNA fragments are separated using electrophoresis
  4. DNA fragments are absorbed onto a nylon membrane and heated to make it single stranded
  5. Radioactive / fluorescent DNA probes are added that are complementary to the VNTRs and probes bind
  6. Autoradiography or UV optical microscopes are used to detect fragments
• What are the uses of genetic fingerprinting?

  1. In forensic science to identify an individual
  2. To determine familial relationships e.g. paternity tests
  3. In medical diagnosis as some genetic diseases are linked to specific VNTR lengths
  4. In animal and plant breeding to reduce the chance of inbreeding and genetic disorder