Punnett Square Review

Name: _______________________
Instructor: ___________________
Punnett Square Review
Date: _______
Period: ______
Complete the Punnett Squares below and list the Genotype and
Phenotype probabilities as fractions and percentages.
Let’s work with Pea Plants like Mendel did. We will look at the possibilities of pod
color. Green is the dominant pod color and yellow is the recessive pod color.
Pick letters: [Green: G ] [Yellow: g ]
Try these combinations…
G G G G G G
G G g
G g g
Genotypes
? / 4 % Genotypes
? / 4 % Genotypes
? / 4 %
Phenotypes Phenotype Phenotype
G g G g g g
G g g
g g g
Genotypes
? / 4 % Genotypes
? / 4 % Genotypes
? / 4 %
Phenotypes Phenotype Phenotype

Now try to do the same thing for right- or left-handedness. Righthandedness
is dominant [R] and left-handedness is recessive [r].
Genotypes
? / 4 % Genotypes
? / 4 % Genotypes
? / 4 %
Phenotypes Phenotype Phenotype
Genotypes
? / 4 % Genotypes
? / 4 % Genotypes
? / 4 %
Phenotypes Phenotype Phenotype
Mr. Jensen is left-handed but both of his parents are right-handed. Look at the Punnett
squares that you completed above and determine which one has two right-handed parents
having left-handed offspring.
1. What are the genotypes of Mr. Jensen’s parents?
Mother’s Genotype:
Father’s Genotype:
2. Using the same Punnett Square, what is the probability of these parents having lefthanded
offspring?
%