Most pedigrees showing the hypothetical human trait show the following characteristics:
• If a phenotypically normal woman with an affected father has children with an unaffected man, half of the sons and none of the daughters are affected.
• Affected females always have an affected father and an affected maternal grandfather.
• The trait is never passed from father to son.
What is the MOST likely mode of inheritance for this disorder?
A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Question

Most pedigrees showing the hypothetical human trait show the following characteristics: 
• If a phenotypically normal woman with an affected father has children with an unaffected man, half of the sons and none of the daughters are affected.
• Affected females always have an affected father and an affected maternal grandfather.
• The trait is never passed from father to son.
What is the MOST likely mode of inheritance for this disorder?
A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Quizplus · Accepted Answer

The trait is X-linked recessive because it is never passed from father to son, affected females have affected fathers, and half of the sons of carrier females are affected.

Most Pedigrees Showing the Hypothetical Human Trait Show the Following