Question

Mr. Kapoor has a autosomal gene pair 'Bb' and he contain X-linked gene 'd' both on of her X-chromosome. What is the percentage of gamete which contain 'bd' genes :-

• A. 1/2 or 50%
• B. 1/4 or 25%
• C. 3/4 or 75%
• D. 1 or 100%

Answer 1

Answer: (B)

1/4 or 25%

Answer 2

Mr. Kapoor’s genotype is heterozygous for the autosomal gene (Bb) and hemizygous for the X-linked gene (d) (since males have only one X-chromosome). Thus, during gamete formation:

• The probability of passing allele “b” from the autosomal pair = 1/2.
• The probability that a sperm is X-bearing (and hence carries the d allele) = 1/2.

Since these events are independent, the overall probability that a gamete gets both “b” and “d” is:

1/2 × 1/2 = 1/4 (which is 25%).