Chapter 2, Problem 10EQ

In fruit flies, curved wings are recessive to straight wings, and ebony body is recessive to gray body. A cross was made between true-breeding flies with curved wings and gray bodies and flies with straight wings and ebony bodies. The ${\text{F}}_{\text{1}}$ offspring were then mated to flies with curved wings and ebony bodies to produce an ${\text{F}}_{\text{2}}$ generation.

A. Diagram the genotypes of this cross, starting with the parental generation and ending with the ${\text{F}}_{\text{2}}$ generation.

B. What are the predicted phenotypic ratios of the ${\text{F}}_{\text{2}}$ generation?

C. Let’s suppose the following data were obtained for the ${\text{F}}_{\text{2}}$ generation:

114 curved wings, ebony body

105 curved wings, gray body

111 straight wings, gray body

114 straight wings, ebony body

Conduct a chi square analysis to determine if the experimental data are consistent with the expected outcome based on Mendel’s laws.