In Thomas Hunt Morgan's experiments, males had white eyes but females did not. What cross could you perform with his flies to obtain white-eyed females?

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Quizplus · Accepted Answer

The white eye trait in Morgan's fruit flies is sex-linked, located on the X chromosome. Females have two X chromosomes, so to express a recessive trait like white eyes, they must inherit the trait from both parents. Crossing females (regardless of their genotype, as long as they can potentially carry a white-eyed allele) with a white-eyed male (who contributes his X chromosome with the white-eyed allele to all his daughters) can produce white-eyed females if the females inherit the white-eyed allele from both parents.

In Thomas Hunt Morgan's Experiments, Males Had White Eyes but Females