Zoology - Principles of Inheritance and Variation Question with Solution | TestHub
A husband and wife have normal vision, although both of their fathers are red-green colour blind, which is inherited as an x-linked recessive trait.
What is the probability that their first child will be?
i. A normal son
ii. A carrier daughter
iii. A colour-blind son
iv. A colour-blind daughter
Options:
Answer:
Solution:
Mother is a carrier (because her father is colour blind) and father is normal. Hence, their genotype is XcX and XY, respectively. Thus, the probability that their first child will be a normal son is 1/4, a carrier daughter is 1/4, colour-blind son is 1/4 and a colour-blind daughter is 0 (both husband and wife have normal vision, though their fathers were colour blind. The probability of their daughter becoming colour blind is 0%. The chances of a daughter becoming colour blind arise only when the father is also colour blind).
