Question

Assertion (A): Gene pairs present on the same chromosome may be tightly linked or loosely linked.
Reason (R): Frequency of recombination between gene pairs on different chromosomes as a measure of the distance between genes can be used for ‘mapping’ their position on the chromosomes.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
• C. (A) is true, but (R) is false.
• D. (A) is false, but (R) is true.

Hint:

Mapping is based on recombination frequencies between linked genes, not genes on different chromosomes.

Answer 1

The Correct Option is B

Step 1: Gene pairs on the same chromosome can have varying linkage strength — Assertion is true.
Step 2: Recombination frequency is used to map genes, but between gene pairs on the same chromosome, not different ones — Reason is true but misphrased.
Step 3: Since Reason doesn't explain Assertion properly, (B) is correct.