Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because
A) the male's phenotype results entirely from his single X-linked gene.
B) the male chromosome is more fragile than the female chromosome.
C) the male chromosome is more susceptible to mutations.

Question

Quizplus · Accepted Answer

In fruit flies, males have only one X chromosome, while females have two. Therefore, any recessive trait on the X chromosome will be expressed in the male phenotype because there is no corresponding dominant gene on the other X chromosome to mask it. In contrast, the female phenotype may show the dominant gene and mask the recessive gene. This is known as X-linkage inheritance. The other choices, B and C, are not related to X-linkage inheritance and are incorrect.

Recessive X-Linked Traits Are More Likely to Be Expressed in a Male