Question

Which one of the following is INCORRECT about DNA fingerprinting?

• A. Every person shows an unusual sequence of 20-100 base pairs of DNA which are repeated several times and called VNTRs.
• B. The length of the regions having VNTRs is different in each individual.
• C. By using restriction enzymes, the DNA is cut into fragments of equal length.
• D. When placed on agarose gel, these fragments which are negatively charged move towards the positive pole.

Hint:

Think about the fragment lengths produced after cutting DNA with restriction enzymes. VNTR numbers differ in each person.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
DNA fingerprinting depends on VNTRs, short sequences of about 20 to 100 base pairs repeated many times.

Step 2: Check each statement
VNTR regions differ in length in each individual, so statement B is correct.
DNA is negatively charged, so it moves toward the positive pole in agarose gel, so statement D is correct.

Step 3: Find the incorrect one
Restriction enzymes cut at specific sites, but the repeat numbers between sites vary. So the fragments have different lengths, not equal lengths.

Final Answer:
The statement that DNA is cut into fragments of equal length is incorrect. \[ \boxed{\text{(C) }\text{By using restriction enzymes, the DNA is cut into fragments of equal length.}} \]