[Campbell Biology P.345] In Morgan's experiment with fruit flies Figure 15.3 , what was the ... | Practice Question

In Morgan's experiment with fruit flies Figure 15.3 , what was the key result in the F2 generation that suggested the white-eye gene was located on the X chromosome?

  • A: The F1 generation all had red eyes.
  • B: The F2 generation showed a 3:1 ratio of red eyes to white eyes.
  • C: In the F2 generation, only males had white eyes.
  • D: The F2 generation showed a 1:1 ratio of red-eyed males to red-eyed females.

Explanation

The text highlights this as the surprising result that deviated from simple Mendelian expectations. The fact that the recessive trait white eyes appeared exclusively in males strongly correlated the inheritance of the trait with the inheritance of sex, leading Morgan to deduce the gene was on the X chromosome.