The sex of the fruit fly Drosophila melanogaster is determined as follows: XX chromosomes give a female and XY give a male. The gene for bar eyes is recessive and located on the X chromosome. If a male with normal eyes is mated with a female who has normal eyes but is heterozygous,

Question

Quizplus · Accepted Answer

Since the bar eye gene is recessive and located on the X chromosome, a male (XY) receiving the X chromosome with the bar eye gene from the heterozygous female (XBXb) will express bar eyes, resulting in half of the male offspring having bar eyes.

The Sex of the Fruit Fly Drosophila Melanogaster Is Determined