Question

A population of captive organisms is produced from two breeding pairs. The males of both breeding pairs possess a Y-linked allele coding for white fur on their ears. Which statement correctly describes how the Y-linked trait will affect the phenotypes seen in the population?

A.
All males and females in the population will have white ear fur.
B.
All females in the population will have white ear fur, but no males will.
C.
All males and females with two copies of the Y-linked allele will have white ear fur.
D.
All males in the population will have white ear fur, but no females will.

Answer 1

The correct answer is: D. All males in the population will have white ear fur, but no females will.

When the trait (in this case, fur color) is Y-linked, it means it will never occur in females.

The Mendelian concept of dominant and recessive do not apply to Y-linked traits, because only one allele (on the Y) is ever present (in male individual). Because only one allele is present, those males are called hemizygous.