Genetics Problems
(ABO Blood System)

The chart below lists the blood phenotypes of 8 individuals.  Use the information in the chart to solve the genetics problems that follow.

Females Blood Type Males Blood Type
Anne Type O Charlie Type A
Wendy Type B Scott Type AB
Susan Type AB Larry Type O
Patricia Type A Keith Type B


1.  Larry has a son with type B blood.  Which of the females listed above could be this child's biological mother?  answer

2.  Anne is pregnant with Scott's child.  What is the chance that the baby will have type A blood?  answer

3.  Because her daughter has type B blood, Patricia insists that Keith is the father.  Keith claims that Scott is the father of Patricia's baby girl.  Is it possible that Scott is the baby's father?   answer

4.  Keith and Wendy have a 4-year old with type O blood.  How is this possible?  answer

5.  Susan is the mother of Charlie's first two children.  The oldest, Dawn, has type AB blood while her sister, Kate, has type B blood.  Charlie is now expecting a baby with Anne.  What is the chance that this child will have type O blood?  answer

6.  Erin, Patricia and Larry's daughter, is married to Jeff.  Jeff was in a serious car accident and needs a transfusion but Erin is told that Jeff cannot be given her blood.  Based on this information, provide Erin's blood genotype and blood phenotype.  answer

7.  Scott and Susan's son, Paul, is willing to donate blood to a young girl with leukemia.  If the recipient has type O blood, will Paul be able to donate to her? answer


















1.  Wendy or Susan could be the biological mother of Larry's son.

Genetic Explanation:
Larry (type O)     Mom (anything w/ at least 1 B allele)
            OO                  B?
                Larry's son (type B) 

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2.  Scott = AB     Anne = OO

     chance of baby with type A blood (AA or AO) = 50%

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3.  Yes, it is possible for Scott to be the father of Patricia's daughter.

Genetic Explanation:
Scott (type AB)     Patricia (type A)
            AB                   AO 
                Patricia's daughter (type B) 

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4.  It is possible if both Keith and Wendy are heterozygous.

Genetic Explanation:
Keith (type B)     Wendy (type B)
            BO                   BO 
                   child (type O) 

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Genetic Explanation for Charlie's Genotype:
Charlie (type A)     Susan (type AB)
            AO                  AB
                Dawn (type AB) 
Kate (type B) 

5.  Charlie = AO     Anne = OO

     chance of baby with type O blood (OO) = 50%


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Explanation of Erin's Genetic Possibilities:
Larry (type O)     Patricia (type A)
            OO                  AA or AO
                Erin (type A or type O) 
                       Aor  OO

6.  Erin must be type A (gentoype AO) because if she was type O, the universal donor, Jeff could have been given her blood.


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Explanation of Paul's Genetic Possibilities:
Scott (type AB)     Susan (type AB)
            AB                  AB 
                Paul (type A or type B or type AB) 
                            AA  or     Bor  AB / AB

7.  Based his parent's genotypes, Paul could be any blood type except type O.  Because the recipient is type O, and type O can only accept type O blood, Paul could not donate to this girl.

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