Drosophila fruit flies are often used as model organisms in genetic research. In Drosophila, eye color is determined by genes on the sex chromosomes, and red eyes (W) are dominant to white eyes (w). Figure 1
shows an example of Drosophila sex chromosomes with alleles for eye color. Figure 2 is a pedigree showing
the inheritance of eye color in Drosophila over four generations. Figure 3 is a Punnett square depicting a cross
between two fruit flies.
A Based on Figure 1, describe a difference between a Y chromosome and an X chromosome.
B. In Figure 1, both the female and the male have one recessive allele, Predict whether the female and
male will express the same trait and justify your claim using evidence from Figure 1.
C. Based on Figure 2, describe the pattern in a pedigree for an X-linked recessive trait.
D. Based on Figure 3, explain why all male offspring are white-eyed and all female offspring are red-eyed.