Reason : They are not recognised by $tRNA$.
$(I)$ Separation of $DNA$ fragment by electrophoresis.
$(II)$ Digestion of $DNA$ by restriction endonucleases.
$(III)$ Hybridization using labeled $VNTR$ probe
$(IV)$ Isolation of $DNA$.
$(V)$ Detection of hybridized $DNA$ fragments by autoradiography.
$(VI)$ Transferring of separated $DNA$ fragment to synthetic membranes.
$A.$ Variation at genetic level arises due to mutations.
$B.$ Technique of $DNA$ fingerprinting was initially developed by Alec Jeffreys