Red-green colour blindness is a recessive X-linked trait in humans.The set of parents that are MOST LIKELY to produce a daughter with red-green colour blindness is a/ an:
Correct answer: A. Carrier mother and a colour blind father
- A. Carrier mother and a colour blind father
- B. Carrier mother and an unaffected father
- C. Colour blind mother and an unaffected father
- D. Unaffected, non-carrier mother and a colour blind father
Explanation
The correct answer is a carrier mother and a color blind father. A carrier mother has one normal X chromosome and one affected X chromosome, while a color blind father has the affected X chromosome. If the daughter inherits the affected X from both parents, she will be color blind. Other combinations either result in daughters who are carriers or unaffected, as they would inherit at least one normal X chromosome, which masks the effect of the recessive X-linked trait.
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About X-linked Recessive Inheritance
X-linked recessive inheritance involves genes on the X chromosome, so males express a recessive allele with no corresponding allele on their single X chromosome, while females may be carriers. Pedigrees cover haemophilia and red-green colour blindness, including carrier mothers, affected sons and the absence of father-to-son transmission.
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