Question

I have the data for corn color and texture. These are the follow up questions for the data.

Color of Corn Grains

Number of Purple (Red) Grains: 75

Number of Yellow (White) Grains: 30

Ratio of Purple (Red) Grains: Yellow (White) Grains: 2.5:1

Probable Genotypes of Parents:  

Texture of Corn Grains

Number of Smooth Grains: 85

Number of Wrinkled Grains: 20

Ratio of Smooth Grains: Wrinkled Grains: 4.25:1

Probable Genotypes of Parents:

Grain color is one trait. Grain texture is a second trait. For each, what do you notice about the phenotypic ratios?

R = Purple/Red; r = Yellow/White; S = Smooth; s = Wrinkled

A genetic cross with only one trait is a monohybrid cross.

A genetic cross involving two traits is called a dihybrid cross.

Consider the cross: RRSS x rrss (Parental Generation) F1 is the result of the cross. (Gametes: RS for one parent (e.g. the egg) and rs for another parent (e.g. the sperm). FOR EACH GAMETE, IT IS ONE ALLELE FOR EACH TRAIT. THIS IS WHY YOU SEE TWO LETTERS PER GAMETE.)

What is the expected genotype for the F1 generation?

Will all F1 offspring have the same genotype?

Will all F1 offspring have the same phenotype?

What are the predicted phenotypes for the F2 generation crossing RrSs x RrSs?

In what ratios will they occur?

Purple/Red, Smooth:

Purple/Red, Wrinkled:

Yellow/White, Smooth:

Yellow/White, Wrinkled:

Answer 1