Brief note on DNA finger printing



The molecular techniques presented so far have proved to be versatile, with ever-increasing uses in science, medicine, industry and other human activities. We present here a few applications that seem interesting and important.

Finger printing with ink and paper, based on fingertip ridge patterns, is the standard method for personal identification. Constant through life, fingerprints can be used to distinguish one person from any other even one identical twin from other, although their patterns are very similar.

The eugenicist Francis Galton began fingerprint classification in the 1890s, making practical the filing and retrieval of records. DNA finger printing has a similar aim, but it is based on certain nucleotide sequences that differ greatly among people (Actually the method should be called simply DNA printing or DNA typing, since it has nothing to do with fingers,) The protocol begins by using a restriction enzyme to cut a person’s DNA into fragments and then using electrophoresis of the fragments to separate different lengths.

Pinpointing specific length differences between people involves some additional techniques. DNA finger printing that is individual specific DNA identification is made possible by the finding that no two people are likely to have the same number of copies of repetitive DNA units at all of the places where the sequences occur.