• DNA finger printing is a very quick way to compare the DNA sequences of any two individual.
  • DNA fingerprinting involves identifying differences in some specific regions in DNA called repetitive DNA, because in these sequences, a small stretch of DNA is repeated many times.
  • During centrifugation the bulk DNA forms major peak and the other small peaks are called satellite DNA.
  • Depending on base composition (A:T rich or G:C rich), length of segment, and number of repetitive units, the satellite DNA classified into many types, such as mini –satellite and micro – satellite.
  • These sequences dose not code for any proteins.
  • These sequences show high degree of polymorphism and form basis of DNA fingerprinting.
  • Polymorphism in DNA sequence is the basis of genetic mapping of human genome as well as of DNA fingerprinting.
  • Polymorphism (variation at genetic level) arises due to mutations.
  • If an inheritable mutation is observed in a population at high frequency it is referred as DNA polymorphism.

The process:

  • DNA fingerprinting was initially developed by Alec Jeffreys.
  • He used satellite DNA as the basis of DNA fingerprinting that shows very high degree of polymorphism. It was called as Variable Number Tandem Repeats.(VNTR)
  • Different steps of DNA fingerprinting are:-
    • Isolation of DNA.
    • Digestion of DNA by restriction endonucleases.
    • Separation of DNA fragments by gel electrophoresis.
    • Transferring (blotting) of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon.
    • Double stranded DNA made single stranded.
    • Hybridization using labeled VNTR probe.
    • Detection of hybridized DNA fragments by autoradiography.

  • The VNTR belongs to a class of satellite DNA referred to as mini-satellite.
  • The size of VNTR varies from 0.1 to 20 kb.
  • After hybridization with VNTR probe the autoradiogram gives many bands of different sizes. These bands give a characteristic pattern for an individual DNA. It differs from individual to individual.
  • The DNA from a single cell is enough to perform DNA fingerprinting.


  • Test of paternity.
  • Identify the criminals.
  • Population diversity determination.
  • Determination of genetic diversity.

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