Question

Name and describe the technique that will help in solving a case of paternity dispute over the custody of a child by two different families?


class 12th CBSE Biology sample paper

Answer 1

The technique that will help in solving a case of paternity dispute over the custody of a child by two different families is DNA Fingerprinting Technique.

The technique of DNA Fingerprinting was initially developed by Alec Jeffreys. He used a satellite DNA as probe that shows very high degree of polymorphism.  It was called as Variable Number of Tandem Repeats (VNTR).  The technique, as used earlier, involved Southern blot hybridisation using radiolabelled VNTR as a probe.

It included :

(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.

Note:The VNTR belongs to a class of satellite DNA referred to as mini-satellite. A small DNA sequence is arranged tandemly in many copy numbers.