Correct option is D
The correct answer is (d) All daughters will carry the mutant allele.
In X-linked inheritance, fathers pass their X chromosome to all of their daughters and their Y chromosome to their sons. Since the father has an X-linked mutation, all daughters will inherit the mutant allele from him. Sons will inherit the Y chromosome from the father, and because the mother is not a carrier, they cannot inherit the mutation and will not show the disorder.
Information Booster:
- X-linked mutations: Passed from father to daughters, not to sons.
- Daughters of an affected father: Always inherit his mutant X chromosome.
- Sons of an affected father: Only inherit the Y chromosome from their father, so they are unaffected.
- Mother is not a carrier: Sons do not receive the mutant X chromosome, ensuring they are unaffected.
- Late-onset lethal X-linked disorders typically do not affect females who are carriers, as the normal allele compensates.
Additional Knowledge:
(a) There is a 50% chance that the son will show the disorder:
This is incorrect. Sons inherit the Y chromosome from the father, so they cannot inherit an X-linked disorder from him. The mother does not carry the mutation, ensuring sons are unaffected.
(b) No children will show the disorder:
This is incorrect. While no sons will show the disorder, all daughters will carry the mutant allele, and they could potentially pass it on to their offspring.
(c) The probability that the parents have a daughter carrying a mutant allele is 25%:
This is incorrect. All daughters will inherit the mutant allele because the father passes on his X chromosome (with the mutation) to all daughters.
(d) All daughters will carry the mutant allele:
This is the correct answer. Since the father has an X-linked mutation, all his daughters will inherit the mutant X chromosome from him, making them carriers of the mutation.
