Question

A woman expresses an X-linked recessive disorder. Select the correct statemet about woman parents?
I. Her mother passed on an allele for the disorder
II. Her father expresses the same disorder
III. Her mother does not express the disorder

• A. I only
• B. II only
• C. I and II only
• D. II and III only
• E. I, II, and III

Answer 1

The correct option is C I and II only

X-linked traits follow criss cross inheritance. Statements A and B are correct as affected daughters obtain one copy of affected X chromosome from affected or carrier mother and other from affected father. Statement III can not be concluded from the given information as a mother of woman can be the carrier or affected one. If the mother is homozygous recessive for the trait, she will express the disorder. The correct answer is C.