Methodology and Technique
i. DNA is isolated and extracted from the cell or tissue by centrifugation.
ii. By the process of polymerase chain reaction (PCR), many copies are produced. This step is called amplification.
iii. DNA is cut into small fragments by treating with restriction endonucleases.
iv. DNA fragments are separated by agarose gel electrophoresis.
v. The separated DNA fragments are visualised under ultraviolet radiation after applying suitable dye.
vi. The DNA is transferred from electrophoresis plate to nitrocellulose or nylon membrane sheet. This is called Southern blotting.
vii. VNTR probes are now added which bind to specific nucleotide sequences that are complementary to them. This is called hybridisation.
viii. The hybridised DNA fragments are detected by autoradiography. They are observed as dark bands on X-ray film.
