1. Punnett Squares Review Worksheet
Name______________________________
Match the following terms to their proper definitions.
A. heterozygous
B. allele
C. codominance
D. incomplete dominance or intermediate inheritance
E. sex-linked
F. homozygous
G. phenotype
H. genotype
1. This is an alternate form of a gene. __________
2. This is when a third physical look is observed that is not like the parents. The two
alleles blend together to create a new look. ___________
3. This is when both alleles are the same.___________
4. This is a trait that is found on the X chromosome only.______________
5. This is the physical look of an organism.____________
6. This is when there are multiple alleles for a trait and more than one allele is
dominant.__________
7. This is when both the alleles are different._____________
8. This is what the genes actually say.______________

2. REMEMBER: ON THE TEST, YOU WILL NEED TO KNOW HOW TO DO EACH
OF THESE SQUARES!
Directions: Read the story problem and using the information given, create a Punnett
square. Then answer the question.
9. Colorblindness is a sex-linked trait. A woman who is a carrier marries a man that
has normal vision. The woman is now pregnant. What is the probability that she
will have a child that is colorblind?
10. Gregor Mendel is mating two plants. One plant has yellow flowers and the other
plant has blue flowers. Gregor Mendel has discovered that these plants have
incomplete dominance. What will the phenotype of the offspring be?
11. There are two squirrels that have mated and produced offspring. One squirrel is
heterozygous for black hair. The other squirrel has brown hair. What is the
probability that the squirrel’s children have black hair?
12. Kelsey is pregnant and she has blood type O. Her husband, Andy is heterozygous
for blood type A. What is the probability that their baby will have blood type O?

3. 13. Two guinea pigs have mated and have had 100 babies. (They were doing it a lot!)
One guinea pig is heterozygous for black hair and the other is homozygous for
brown hair. The black allele is dominant over the brown allele. How many
offspring would you expect to be black?
14. A baby horse is born that has pink hair. The mother has plain black hair. How
could this have happened? Explain your answer giving an example using the
father.