Question

What will be the percentage of sons having a normal vision if the father has normal vision and their mother is colour blind?

(a) 0%

(b) 25%

(c) 50%

(d) 100%

The question was posed to me during an online interview.

The query is from Inheritance and Variation Principles topic in section Principles of Inheritance and Variation of Biology – Class 12

Answer 1

The correct option is (a) 0%

For explanation I would say: The percentage of sons having normal vision, if the father has normal vision and mother is colour blind is 0% because as colour blindness is a sex-linked trait, it means that the trait only transmits through X-chromosome. As the mother is colour blind, both her gametes will carry the gene for colour blindness, so none of their sons will have a normal vision.