Q. A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colour blind ?
A) 0.25
B) 0.5
C) 1
D) Nil
Explanation
[Solution] All daughters are carriers and sons are normal. The source keys (4) Nil, treating the grandson as a son's son, since a son receives no X-linked allele from the colour-blind father. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.