Sex-Linked Inheritance Problem Set

Problem 3: Predicting the offspring of a homozygous red-eyed female fly

Tutorial to help answer the question

In a cross between a pure bred, red-eyed female fruit fly and a white-eyed male, what percent of the male offspring will have white eyes? (white eyes are X-linked, recessive)


Genotypes and phenotypes of parents

The pure bred female is homozygous for the normal X chromosome.

The white-eyed male is hemizygous for the X chromosome with a white eye mutation.

Genotypes and phenotypes of offspring

Both male and female children will inherit a normal X chromosome from the female.

None of the male or female offspring will have white eyes.

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University of Arizona
Updated: July 15, 1999
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