dna fingerprinting

• DNA Fingerprinting


  A laboratory technique used to determine the probable identity of a person based on the nucleotide sequences of certain regions of human DNA that are unique to individuals
• DNA Fingerprinting


  Also known as Restriction Fragment Length Polymorphisms (RFLPs)
• Applications of DNA Fingerprinting

  • Identifying a microbe causing an infection (diagnostic test)
  • Identifying microbes for scientific research
  • Paternity testing
  • Forensic DNA analysis to match DNA to criminal suspects
  • A wide variety of genetic research
• Each individual's banding patterns should be different because the restriction enzymes will cut each person's DNA at different points
• Creating a DNA Fingerprint

  Gel Electrophoresis - a technique commonly used to separate biological molecules based on size and biochemical characteristics, such as charge and polarity
• DNA molecules have an overall negative charge due to negative charges on the phosphate groups of its nucleotides
• Small DNA fragments travel farther through the electrophoresis gel than larger DNA fragments
• Steps of DNA Fingerprinting


  1. DNA is extracted from the specimen (i.e., blood, semen, skin, hair)

  2. Restriction enzymes are added, which work like scissors to cut the DNA into the smaller segments that are different between individuals

  3. DNA segments are sorted by agarose gel electrophoresis and visualized by staining with ethidium bromide

  4. A Southern blot is performed to transfer the DNA onto a membrane

  5. A radioactive probe is applied to the membrane, and the pattern of DNA is detected by exposing the membrane to x-ray film

  6. The result is a pattern of DNA bands that looks like a supermarket bar code
• The findings: they found out that some short repeating sequences were homologous between seals and humans
• Sir Alec Jeffreys, professor and geneticist at the University of Leicester in the United Kingdom (UK), pioneered DNA-based identity testing
• Sir Alec Jeffreys was interested in studying the genetic variation between individuals and had done some of the early work to detect genetic differences in humans
• Myoglobin is a protein that is found in the striated muscles, which includes skeletal muscles (the muscles attached to your bones and tendons) and heart muscles
• Myoglobin's main function is to supply oxygen to the cells in your muscles (myocytes)
• All cells in your body need oxygen in order to function