Question Detail
Question
A couple with normal vision had colour blind father each. What is the percentage of probability that the daughter of the couple is colour blind?
Correct Answer
Option D is the correct answer.
Detailed Explanation
Color blindness is an X-linked recessive disorder. Since both parents have normal vision but each had a color-blind father, the mother must be a carrier (X^C X^c) and the father is normal (X^C Y). A daughter inherits an X^C from her father. From her mother, she has a 50% chance of receiving X^C (carrier) and a 50% chance of receiving X^c (normal). Since she always receives a normal X from her father, she will never inherit two recessive alleles and thus will not be colorblind. She has a 50% chance of being a carrier, but 0% chance of being affected.
Hint
Analyze the inheritance pattern of X-linked recessive traits, focusing on the alleles passed from parents to daughters.