When Thomas Hunt Morgan crossed his red-eyed F₁ generation flies to each other, the ?F₂ generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
A)The gene involved is on the Y chromosome.
B)The gene involved is on the X chromosome.
C)The gene involved is on an autosome, but only in males.
D)Other male-specific factors influence eye colour in flies.
E)Other female-specific factors influence eye colour in flies.

Question

Quizplus · Accepted Answer

The gene involved in determining eye color is located on the X chromosome, and since males only inherit one X chromosome (from their mother), they express the trait according to that one copy they have. This explains why all the white-eyed flies in the F₂ generation were male.

When Thomas Hunt Morgan Crossed His Red-Eyed F₁ Generation Flies