Study Guide 5 Sex-Linked Inheritance (Fruit Flies)

Question 1

In fruit flies, eye color is a sex linked trait. Red (XR) is dominant to white (Xr)

a) What are the sexes and eye colors of flies with the following genotypes:

Answer 1

Question 2

In fruit flies, eye color is a sex linked trait. Red (XR) is dominant to white (Xr)

b) What are the genotypes of the following fly phenotypes (NOTE: there may be more than one possible genotype):

Answer 2

Question 3

Draw the potential results of a cross between a white eyed female fly with a red-eyed male.

a) What percentage of the male offspring would you expect to have red eyes? Explain your answer

b) What percentage of the female offspring would you expect to have white eyes? Explain your answer

Answer 3

a) None, because they
inherit a white allele from the mother

b) None, because
they inherit a red allele from the father