1. SBI 3U
Multiple Alleles

2. Multiple Alleles: Human Blood Groups
In humans a single gene controls a person’s ABO blood type
This gene determines what type of an antigen protein is attached to membrane of a red blood cell
Three alleles A,B and O

3. Multiple Alleles Three blood type alleles: IA, IB , i
The alleles for blood types A and B are codominant
Blood type O is homozygous recessive
BLOOD GROUPS
PHENOTYPE
GENOTYPE

4. BLOOD TYPES
A human blood group or “type” is a group of red blood cells that have the same antigen protein markers on the cell surface
There are four human blood groups:
A, B, AB, O

5. BLOOD TYPES Blood Type % Amongst Canadians Can Receive From
Can Donate To A 42
A, O
A, AB B 9
B, O
B, AB AB 3
A, B, AB, O O 46
AB = Universal recipient (can receive from anyone)
O = Universal donor (can donate to anyone)

6. Question: Multiple Alleles
A woman with A type blood marries a man with B type blood. They have a child with type O blood.
The man says the child cannot be his. Is he correct? Show your work to prove you are right.
If this child belongs to this father, what were the chances of having this child with type O blood.

7. 2. If a woman has AB blood, and a man has type A blood, what are the possible blood types of their offspring?