Arrange the following steps of DNA fingerprinting in correct sequence :(a) Gel electrophoresis(b) Isolation of DNA(c) Southern blotting(d) Restriction digestion

Answer: (b) Isolation of DNA → (d) Restriction digestion → (a) Gel electrophoresis → (c) Southern blotting

1. Isolation of DNA from a sample such as blood, hair root, semen or skin cells (amplified by PCR if the amount is small).
2. Restriction digestion: the DNA is cut into fragments by restriction enzymes.
3. Gel electrophoresis: the fragments are separated according to size on agarose gel.
4. Southern blotting: the separated fragments are transferred to a nitrocellulose/nylon membrane, which is then hybridized with labelled VNTR probes and autoradiographed to get the band pattern (fingerprint).