DNA Fingerprinting

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"(DNA technology) − The most awesome and powerful tool acquired by man since the splitting of atoms" - The Time Magazine (USA)"

Conventional fingerprint of an individual comes from finger tip and unique for an individual. This is used for identification of a person in forensic lab, police station etc. However, the major drawback of the conventional fingerprints is that it can be changed by surgery. There is another type of fingerprint unique to an individual called DNA fingerprint. This remains same in all body parts, tissues and cells as well as cannot be altered by any known methods. Thus, DNA fingerprint method is becoming primary method for identifying an individual.

We have already studied about DNA structure and recombinant DNA technology etc. The DNA of every human being on the planet is 99.9% same. However, 0.1% of DNA is unique to the individual that makes all the difference. These differences are a consequence of mutations during evolution. As single change in nucleotide may make a few more cleavage site of a given nucleotide or might abolish some existing cleavage site (Please recall our discussion about restriction enzymes; Type II restriction enzyme cuts at a given nucleotide sequence). Thus, if DNA of any individual is digested with a restriction enzyme, fragments pattern (sizes) will be produced and will be difference in cleavage site position. This is the basics of DNA Fingerprinting. DNA Fingerprinting is used by scientists to distinguish between individuals of the same species using only samples of their DNA. The process of DNA Fingerprinting was invented by Sir Alec Jeffrey at the University of Leicester in 1985.