In 1910,Morgan did a series of experiments with the fruit fly Drosophila,an organism where females are XX and males are XY.When a mutant male fly with white eyes was crossed with a wild type female with red eyes,none of the F₁ progeny had white eyes but 18% of the F₂ progeny had white eyes.Unexpectedly,all of these white-eyed F₂ flies were males.Based on these results,Morgan concluded that white eyes is caused by a recessive X-linked allele.Suppose Morgan had found that half of the F1 progeny had white eyes but all of these white-eyed F₁ flies were females.In this case,a valid hypothesis would be A)White eyes is caused by a recessive Y-linked allele. B)White eyes is caused by a dominant Y-linked allele. C)White eyes is caused by a dominant X-linked allele. D)White eyes is caused by a dominant autosomal allele.

Question

Quizplus · Accepted Answer

If half of the F1 progeny had white eyes and all were females, it suggests that the white-eye trait is dominant and linked to the X chromosome. Since females have two X chromosomes, they would express the trait if they inherit one dominant allele.

In 1910,Morgan Did a Series of Experiments with the Fruit