Question

Some of the steps followed for molecular diagnosis of a pathogen are given. Identify their correct sequence from the options given below.
I. Electrophoresis of DNA fragments
II. Hybridisation with DNA probe
III. Digestion of DNA by restriction endonucleases
IV. Autoradiography
V. Transferring of DNA fragments on nitrocellulose membrane

• A. III – I – II – V – IV
• B. III – I – V – II – IV
• C. I – V – III – II – IV
• D. I – III – V – IV – II

Answer 1

The correct option is B III – I – V – II – IV

Biotechnology has proven useful in early diagnosis of a disease.

The following are the steps of Southern blotting and can be followed for an early detection of a disease.

(I) Isolation of DNA from the organism
(II) Digestion of DNA by restriction endonucleases
(III) Separation of digested DNA fragments by electrophoresis
(IV) Transferring of separated DNA fragments to synthetic membranes like nitrocellulose or nylon membranes
(V) Hybridisation of DNA by using radioactive probe
(VI) Detection of hybridised DNA fragments by autoradiography