Download Blood Typing Practice

Name_____________________________
Date_________
Multiple Alleles: Inheritance of Blood Types
Codominance Inheritance
Geneticists probably know more about blood types than any other inherited human traits. The four basic blood types are
determined by the presence or absence of the A and B agglutinogens in the red corpuscles. For clarity, consider blood types as
being determined by a single pair of genes, I and i.
Type A blood = IAIA or IAio
Type B blood = IBIB or IBio
Type AB blood = IAIB
Type O blood = ioio
Using the Punnett square below, cross a heterozygous parent for Type-A
with another having Type AB blood. Then answer the following
questions.
blood
a. What is the genotype of the parent having type-A blood?______________________________________________________
b. What is the genotype of the parent having type-AB blood?_____________________________________________________
c. What genes for blood type may be passed from the type-A parent to the offspring?__________________________________
d. What genes for blood type may be passed from type-AB parent to the offspring?___________________________________
e. What genotypes might be inherited by the offspring?_________________________________________________________
f. What blood types might be inherited by the offspring?________________________________________________________
g. What blood types are not possible to be inherited by the offspring?______________________________________________
h. Are any of the offspring homozygous for a type of blood? What are they?________________________ ________________
i. Are any of the homozygous for the recessive allele?___________________________________________________________
j. Is the gene for the recessive allele present in any of the offspring?_______________________________________________
k. What blood type does the offspring with the recessive allele possess?____________________________________________
l. What percentage of offspring might be expected to have the same blood as the type-A parent?_________________________
m. What percentage of the offspring might be expected to have the same blood as the type-AB parent?
____________________________________________________________________________________
Determining blood type possibilities in offspring
In this section you will become familiar with the blood types that are possible in offspring resulting from the crossing of parents having
different blood types.
Using the table provided, determine all possible genotypes of the parents, all possible genotypes of the children, all possible blood types, and
blood types not possible in the children.
Blood Type of Parents
All possible genotypes
of parents
All possible genotypes
of children
All possible blood types
of children
Blood types not
possible for children
A and O
B and O
A and B
AB and A
AB and B
AB and O
O and O
1. Mrs. Doe and Mrs. Roe had babies at the same hospital at the same time. Mrs. Roe brought home a baby girl named Nancy. Mrs. Doe
have a baby boy named Richard. . However, she was sure she had had a girl and brought a suit against the hospital. Blood tests showed that
Mr. Doe was type O, Mrs. Doe was type AB, and Mr. and Mrs. Roe were both type B. Nancy was type A and Richard was type O. Had an
exchange occurred?
List all possible genotypes of all the people involved:
Mrs. Doe__________________________________
Mrs. Roe_____________________________
Mr. Doe___________________________________
Mr. Roe______________________________
Nancy______________________________
Richard_____________________________
2. Write a story about blood types. Be creative!!
_________________________________________________________________________________________________________________
_________________________________________________________________________________________________________________
_________________________________________________________________________________________________________________
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3. Now have your neighbor solve your problem. Did she/he get it right? Why or why
not?______________________________________________________________________________________________________________
_________________________________________________________________________________________________________________
Signature of neighbor_________________________________________________________________________
4. Can blood type always determine whether a child belongs to a certain set of parents? Why or why not?__________________
______________________________________________________________________________________________________