Question

A trait controlled by a gene located on either sex chromosome is called a sex-linked trait. In human genetics, however, this term has historically referred specifically to a trait controlled by a gene on the X chromosome (also called an X-linked trait).

In this tutorial, you will explore the pattern of inheritance of sex-linked traits in humans and other animals. The inheritance of a skin condition in humans


Consider the following family history:

Bob has a genetic condition that affects his skin.

Bob’s wife, Eleanor, has normal skin. No one in Eleanor’s family has ever had the skin condition.

Bob and Eleanor have a large family. Of their eleven children, all six of their sons have normal skin, but all five of their daughters have the same skin condition as Bob.


Based on Bob and Eleanor’s family history, what inheritance pattern does the skin condition most likely follow?


X-linked recessive

autosomal recessive

autosomal dominant

X-linked dominant

Y-linked

Answer 1

X-linked dominant

Step-by-step explanation:

The father has the trait. The father is XY with his trait being in X

The mother has no trait. The mother is xx with no trait.

both daughters must be Xx because they have the dominant affected trait.

This is an example of X-linked dominant.