Question

In studying an X-linked dominant trait, you examine a family with seven children. None of the three sons has the trait and all four daughters have the trait. What is the likely conclusion about the parents?

1) The mother has the X-linked dominant trait
2) Both mother and father have the X-linked dominant trait
3) This mutation likely arose during meiosis of either parent
4) The father has the X-linked dominant trait.
5) We do not have enough data to conclude anything

Answer 1

The mother likely has the X-linked dominant trait.

Step-by-step explanation:

The likely conclusion about the parents in this scenario is that the mother has the X-linked dominant trait.

In X-linked dominant inheritance, a heterozygous or homozygous affected female will pass on the trait to all of her children, both male and female.

In this case, since none of the three sons have the trait but all four daughters do, it indicates that the trait is present in the mother.