Question

Arrange the following steps of DNA fingerprinting in a correct sequence.
A. Isolation of DNA and its digestion by restriction endonucleases.
B. Hybridisation using labelled VNTR probe.
C. Transferring of separated DNA fragments to synthetic membranes.
D. Detection of hybridised DNA fragments by autoradiography.
E. Separation of DNA fragments by electrophoresis. Choose the correct answer from the options given below:

• A. A, B, D, C, E
• B. A, E, C, B, D
• C. A, D, B, E, C
• D. A, E, B, C, D

Hint:

The process flow: \textbf{Cut} (A) $\rightarrow$ \textbf{Separate} (E) $\rightarrow$ \textbf{Transfer} (C) $\rightarrow$ \textbf{Probe} (B) $\rightarrow$ \textbf{Detect} (D).

Answer 1

The Correct Option is B

Step 1: Understanding the Question
The objective is to order the laboratory procedures of DNA fingerprinting (Southern Blotting technique) into the correct chronological sequence. DNA fingerprinting is used to identify the unique "barcode" of an individual's DNA. Step 2: Key Formula or Approach
Think about the physical logic of the experiment. You must get the DNA, cut it, sort it, move it to a stable surface, tag it, and finally see it. Step 3: Detailed Explanation
A (Isolation/Digestion): First, you extract DNA from a sample (Isolate) and use "molecular scissors" (Restriction enzymes) to cut it into fragments.
E (Separation): You use Gel Electrophoresis to sort the fragments by size.
C (Transferring): Since the gel is floppy and fragile, you transfer (blot) the DNA fragments onto a synthetic nylon or nitrocellulose membrane.
B (Hybridisation): You wash the membrane with radioactive or fluorescent VNTR probes. These probes "Hybridise" by sticking to their complementary matches.
D (Detection): You use X-ray film (Autoradiography) to see where the probes stuck, creating the final image.
Step 4: Final Answer
The correct sequence is A (Isolate/Cut) $\rightarrow$ E (Sort) $\rightarrow$ C (Transfer) $\rightarrow$ B (Probe) $\rightarrow$ D (See). This corresponds to A, E, C, B, D, which is option (3).