Question

A small fragment of skin of a different person was extracted from the nails of a murdered person. This fragment of skin led the crime investigators to the murderer. Based on this incident answer the following questions:

(1) What technique was used by the investigators? 

(2) What is the procedure involved in this technique?

Answer 1

1) DNA finger printing 

(2) The technique, is based on following procedure 

(i) isolation of DNA,

(ii) digestion of DNA by restriction endonucleases, 

(iii) separation of DNA fragments by electrophoresis, 

(iv) transferring (blotting) of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon,

(v) hybridisation using labelled VNTR probe, and 

(vi) detection of hybridised DNA fragments by autoradiography