Genetic experiments by Thomas Hunt Morgan and colleagues examined eye color in Drosophila fruit flies. Males are XY and females are XX, and the gene responsible for eye color is on the X chromosome. Red eye color (wild-type) is dominant to white eye color (mutant) . The wild type allele is denoted X^w+and the mutant allele isX^w.
Rarely, ova receive two X chromosomes or no X chromosomes. Offspring resulting from these ova helped to determine the factors underlying sex determination in Drosophila. In a cross between X^w/X^w and X^w+/Y, which offspring of faulty ova could be distinguished from normal offspring by phenotype alone? Please select all that apply.

Question

Quizplus · Accepted Answer

The normal offspring of a cross between X^w/X^w and X^w+/Y are as follows: X^wX^w+ (red-eye female) and X^wY (white-eye male). Therefore X^wX^wY (white-eyed female) and X^w+O red-eyed male are different from the expected, and can be distinguished by phenotype alone. X^wX^wX^w+has the same phenotype as X^wX^w+ (red-eye female) and cannot be distinguished by phenotype alone. OY dies and cannot therefore be distinguished phenotypically from offspring that die for other reasons.

Genetic Experiments by Thomas Hunt Morgan and Colleagues Examined Eye