1. Punnett Square
Practice Problems

2. Create a punnett square to determine percent probabilities of genotypes and phenotypes of the offspring of a pea plant with yellow pods crossed with a plant that is heterozygous for pod color. (Green pod color is dominant.)

3. Phenotype ratios Green pods 50% Yellow pods 50%
g g
Genotype ratios
Gg 50%
gg 50% G g Gg Gg gg gg
Phenotype ratios
Green pods 50%
Yellow pods 50%

4. Create a punnett square to determine percent probabilities of genotypes and phenotypes of the offspring of two pea plants that are both heterozygous for seed shape. (Round shape is dominant over wrinkled.)

5. Phenotype ratios Round seeds 75% Wrinkled seeds 25%
R r
Genotype ratios
RR 25%
Rr 50%
rr % R r Rr RR rr Rr
Phenotype ratios
Round seeds 75%
Wrinkled seeds 25%

6. Create a punnett square to determine percent probabilities of genotypes and phenotypes of the offspring of two pea plants that both are homozygous for yellow seed color. (Yellow color is dominant over green.)

7. Phenotype ratios Yellow seeds 100%
Y Y
Genotype ratios
YY % Y YY YY YY YY
Phenotype ratios
Yellow seeds 100%

8. Create a punnett square to determine percent probabilities of genotypes and phenotypes of the offspring of a pea plant that is homozygous for yellow seed color with a plant with green seeds. (Yellow color is dominant over green.)

9. Phenotype ratios Yellow seeds 100%
Y Y
Genotype ratios
Yy 100% y Yy Yy Yy Yy
Phenotype ratios
Yellow seeds 100%

10. Create a punnett square to determine percent probabilities of genotypes and phenotypes of the offspring of a pea plant that is homozygous for green pod color with a plant that is heterozygous for pod color. (Green pod color is dominant over yellow.)

11. Phenotype ratios Green pods 100%
G G
Genotype ratios
GG %
Gg % G g GG GG Gg Gg
Phenotype ratios
Green pods 100%