M ULTIPLE A LLELES
Blood Types

A, B, O B LOOD T YPE S YSTEM
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Multiple alleles – more than two alleles control a trait
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A, B, O System
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Alleles are either A, B, or O
Blood types can be A,
B, AB, or O
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Example – Human
Blood Types 
Blood type is determined by the type of antigen present on the surface of the red blood cell

A NTIGENS AND A NTIBODIES
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Antigens – stimulates an immune response when a foreign substance enters the body
Antigens produce antibodies
Antibodies are like
“soldiers,” they destroy foreign substances

B LOOD T YPES

D ONORS AND R ECIPIENTS
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Which blood type(s) can A, B, AB, and O receive?
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Which blood type(s) can A, B, AB, and O donate to?

Blood Type
A
B
*AB
Universal recipient
*O
Universal donor
Can get blood from…
O, A
O, B
A, B, AB, O
O
Can donate to…
A, AB
B, AB
AB
A, B, AB, O

M OST /L EAST C OMMON B LOOD TYPE
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R H S YSTEM
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Rh is an antigen that is sometimes present on the surface of red blood cells
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85% of the United States population is Rh positive
(Rh+).
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This means that they carry the Rh antigen
People who do not have the Rh antigen are called Rh negative (Rh-)
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Called the Rh factor
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Named after the rhesus monkey in which it was first discovered
Rh+ is dominant over Rh-

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People who are Rh- CANNOT receive blood from a person who is Rh+!
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If an Rh- person receives a transfusion that is Rh+
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 the Rh- person will make antibodies against the Rh+ blood
The antibodies will react with the antigens of the Rh+ blood and the two blood types will clump
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This clumping is called AGGLUTINATION

R H AND P REGNANCY
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If mom is Rh- and dad is
Rh+ = baby will be Rh+
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During delivery baby’s blood may get into mom’s bloodstream and she will make antibodies against the Rh+ blood
If she gets pregnant again her antibodies against Rh+ blood can cross her placenta and attack baby
#2 Rh+ blood

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P RACTICE COPY IN YOUR NOTES
=)
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If one parent has type O blood and the other parent has type AB, what are the possible blood types the offspring could have?
O O
A O A O
A
B O B O
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B

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If both parents are rH+ , is it possible to have a child that is rH- ???

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If both parents are type AB, what are the possible blood types of the offspring?

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If one parent is type A and the other parent is type AB, what is the chance of having a child with AB?

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If one parent is type A and the other parent is type B is it possible for them to have an AB child?

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If one parent is A and the other parent is B, is it possible for them to have a child with type O?

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If one parent is type A and rH+ and the other parent is B and rH+ is it possible to have a child that is type AB and rh- ? Hint, do your Punnett squares separately!

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If one parent is type AB and rH+ and the other parent is AB and rH+, what is the chance of having a child that is type B and rH-?
Hint, both parents are heterozygous for rH factor.