Question

A woman has an X-linked condition on one of her X chromosomes. This chromosome can be inherited by

• A. Only daughters
• B. Only grandchildren
• C. Only sons
• D. Both sons and daughters

Answer 1

The Correct Option is D

An X-linked condition is associated with the X chromosome, one of the sex chromosomes that determine an individual's sex. Since women possess two X chromosomes, they can be carriers of X-linked conditions if one of their X chromosomes carries the defective gene.

When passing on genetic information to their offspring, women can transfer one of their two X chromosomes to each child:

1. Sons: Sons inherit one X chromosome from their mother and one Y chromosome from their father. Therefore, a son of a mother with an X-linked condition has a 50% chance of inheriting the affected X chromosome.
2. Daughters: Daughters inherit one X chromosome from each parent. Consequently, a daughter of a mother with an X-linked condition has a 50% chance of being a carrier if she inherits the affected X chromosome.

Therefore, both sons and daughters can inherit the X-linked condition from their mother.

Let's evaluate the given options:

• Only daughters: Incorrect, since sons can also inherit the X-linked condition if the affected X chromosome is passed on.
• Only grandchildren: Incorrect, because the question refers to direct inheritance by children, not grandchildren.
• Only sons: Incorrect, since daughters can also inherit the affected X chromosome and be carriers.
• Both sons and daughters: Correct, as explained, both can inherit the X chromosome that carries the condition.

Thus, the correct answer is: Both sons and daughters.