Download Blood Types Punnett Squares

Blood Type
Blood type is an example of a single gene that has multiple alleles in humans. One gene codes for proteins on the
surface of red blood cells. Each of the three alleles (A, B, or O) is a code for a different protein on the surface of the red
blood cells. The B allele produces b type proteins, the A allele produces a type a type proteins, and the O allele does not
produce any proteins. Your immune system recognizes the proteins on your red blood cells and identifies them as
belonging to you. If cells with a different protein enter your body, your immune system will attack them. Alleles A and
B are co-dominant. The O allele is recessive. As a result, the following blood types in humans are possible:
Genotypes
AA or AO
BB or BO
AB
OO


Surface Protein
A
B
A and B
None
Phenotypes
A
B
AB
O
A person with type O blood is a universal donor = can donate to any other blood type because there are no surface proteins
A person with type AB is a universal recipient = they can receive blood from anyone because they have both types of proteins.
Using the information provided in each problem:
A. Give the genotypes of the parents
B. Complete the genetic cross in the Punnett Square
C. Give the possible genotypic ratio of the offspring
D.
Give the possible phenotypic ratio of the offspring
1. A father has type AB blood. A mother is heterozygous for type B blood.
A. Parent Genotypes ___________ x ___________
B.
C. Genotypic Ratio: __________________
D. Phenotypic Ratio: _________________
E. What chance do they have of having a child with type A blood? _________
F. What chance do they have of having a child with type B blood? _________
G. What chance do they have of having a child with type AB blood? _________
H. Is it possible for any of the children to receive blood from their father? _________ Why or why not?
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2. A father has type O blood. A mother is homozygous for type B blood.
A. Parent Genotypes ___________ x ___________
B.
C. Genotypic Ratio: __________________
D. Phenotypic Ratio: _________________
E. What chance do they have of having a child with type B blood? _____
F. If the father becomes injured and needs a blood transfusion will he be able to receive blood from his
wife? His child? Explain.
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G. If one of their children become injured which parent would they be able to receive blood from? Why?
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3. A father has type AB blood. A mother has type AB blood.
A. Parent Genotypes ___________ x ___________
B
C. Genotypic Ratio: __________________
D. Phenotypic Ratio: _________________
E. What is the couple’s chance of having a child with type AB blood? __________
F. What is the couple’s chance of having a child with type A blood? __________
G. Could the mother receive a blood transfusion from all of her children or only some? Explain
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4. A father is heterozygous for type A blood. A mother is heterozygous for type B blood.
A.
Parent Genotypes ___________ x ___________
B
C. Genotypic Ratio: __________________
D. Phenotypic Ratio: _________________
E. What is their chance of producing a child with type O blood? _______
F. What is their chance of producing a child with type B blood? _______
G. Could all of the children safely receive a blood transfusion from their mother? Explain
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5. Why is a person with type O blood considered to be a universal donor?
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