2. A researcher crosses a white-eyed female Drosophila with a red-eyed male. Knowing that the gene for eye color is sex-linked, he expects to observe only red-eyed females and white-eyed males in the progeny. However, he observes that while most of the progeny are as expected, a small percentage of the females have white eyes. Explain what may have occurred to cause this result. (5 points)