Fruit flies (Drosophila melanogaster) with a wild-type phenotype have gray bodies and red eyes. Certain mutations can cause changes to these traits. Mutant flies may have a black body and/or cinnabar eyes. To study the genetics of these traits, a researcher crossed a true-breeding wild-type male fly (with gray body and red eyes) with a true-breeding female fly with a black body and cinnabar eyes. All of the F1 progeny displayed a wild-type phenotype. Female flies from the F1 generation were crossed with true-breeding male flies with black bodies and cinnabar eyes. The table on the next page represents the predicted outcome and the data obtained from the cross. Explain the difference between the predicted and observed data. F, Generation Phenotypes
Body Color Eye Color Number predicted Number Observed
Gray Red 244 455
Black Cinnabar 244 432
Gray Cinnabar 244 42
Black Red 244 47