Question

Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly

because
A) the male chromosome is more fragile than the female chromosome.
B) the male chromosome is more susceptible to mutations.
C) the male's phenotype results entirely from his single X-linked gene.
D) males are haploid.

Answer 1

Recessive X-linked traits are more likely to be expressed in male fruit flies because males have only one X chromosome, making them hemizygous for any X-linked trait. In contrast, females have two X chromosomes and need to inherit two copies of the recessive allele to express the trait.

Step-by-step explanation:

Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because males have only one X chromosome, making them hemizygous for any X-linked trait. This means that if a male inherits a recessive X-linked allele, it will be expressed because there is no second copy of the allele to mask its expression. On the other hand, females have two X chromosomes, so they need to inherit two copies of the recessive allele to express the trait. This makes X-linked traits appear more frequently in males than females.