KCET 2014 Biology Solved Paper

The various steps in DNA fingerprinting are:
→ DNA isolated from samples is digested with restriction endonucleases
→ The DNA molecules are separated by gel electrophoresis by Southern blot hybridization.
→ They are then transferred onto nitrocellulose or nylon membranes for immobilization, a process called Southern blot.
→ A radioactively labeled VNTR DNA probe containing the sequence of interest is then hybridized with the immobilized DNA on the membrane
→ Hybridization takes place with only those DNA molecules that contain a nucleotide sequence complementary to the sequence of the probe. Non-hybridized probe is then washed off the membrane.
→ The washed membrane is exposed to X-ray film to detect the presence of the radioactivity. Hence, it can be detected by autoradiography.