The real father can be identified by DNA finger printing technique.
* VNTR (variable number of tandem repeats) are satellite DNAs that show high degree of polymorphism.
* VNTRs are used as probes in DNA fingerprinting.
* First of all, DNA from an individual is isolated and cut with restriction endonucleases.
* Fragments are separated according to their size and molecular weight on gel electrophoresis.
* Fragments separated on electrophoresis gel are blotted (immobilised) on a synthetic membrane such as nylon or nitrocellulose.
* Immobilised fragments are hybridised with a VNTR probe.
* Hybridised DNA fragments can be detected by autoradiography.
* VNTRs vary in size from 0.1 to 20 kb.
* Hence, in the autoradiogram, band of different sizes will be obtained.
* These bands are characteristic for an individual. They are different in each individual, except identical twins.