Question

White eyes in Drosophila melanogaster result from an X-linked recessive mutation. Occasionally, white-eyed mutants give rise to offspring that possess white eyes with small red spots. The number, distribution, and size of the red spots are variable. Explain how a transposable element, or transposon, could be responsible for this spotting phenomenon.

Answer 1

It is not possible that a transposon would get introduced into similar locus in various eye cells. Though the transposons that take place in the differentiating cells can eventually influence various cells. The existence of a transposon in the locus of the eye color affects the generation of red pigment.

Thus, excision of a transposable element out of the locus of the eye color at the time of the development of an eye generates a patch of cells, which generate red pigment.