Principles of Inheritance and Variation Question 206
206. Of both normal parents, the chance of a male child becoming colour blind are
[1993]
(a) no
(b) possible only when all the four grand parents had normal vision
(c) possible only when father’s mother was colour blind
(d) possible only when mother’s father was colour blind
Show Answer
Answer : d
Hints & Solution
(d) On crossing carrier colour blind woman with a normal man, the sons become colour blind. This is an example of criss cross inheritance. The genes for colourblindness is coming from mother’s father.
