Question

A person whose father is colourblind marries a lady whose mother is daughter of a colourblind man. Their children will be having which of the following conditions?

• A. All normal
• B. All colour blind
• C. All sons colour blind
• D. Some sons normal and some colour blind

Answer 1

The correct option is D Some sons normal and some colour blind

A person whose father is colour blind will be normal because genes for color blindness are located on X- chromosome, which will not be transferred to the son, instead it is transferred into only the daughters. If this person marries a lady whose mother is daughter of colour blind father i.e. lady is carrier for colour blind gene. Thus if a normal man marries a carrier lady for colour blind gene, then some of their sons will be normal while some will be color blind.

So, the correct answer is D 'Some sons normal and some colour blind'