Question

Vision of the children born to a colour blind father and normal homozygous mother is

• A. Normal
• B. Females colour blind, males normal
• C. Males colour blind, females carriers
• D. Colour blind

Hint:

Colour blindness follows an X-linked recessive inheritance pattern. A male inherits his X chromosome from his mother, while a female inherits one X chromosome from each parent.

Answer 1

The Correct Option is A

Step 1: The inheritance of colour blindness follows an X-linked recessive pattern. Since the father is colour blind, his genotype must be \( X^bY \), where \( X^b \) represents the X chromosome carrying the colour blind allele. The mother is normal homozygous, so her genotype is \( X^N X^N \), where \( X^N \) represents the normal allele.
Step 2: The offspring can inherit either the \( X^b \) or \( X^N \) chromosome from the mother. The male child will inherit the \( Y \) chromosome from the father, and the \( X^N \) chromosome from the mother, resulting in a normal male child. The female child will inherit one \( X^N \) chromosome from each parent, resulting in a normal female child as well.
Thus, the vision of the children will be normal.