Blood Typing
Blood types
There are 4 blood types
A
B
AB
O
Blood Types
Blood type alleles:
 IA : produces A antigens on
surface of cell (dominant)
 IB : produces B antigens
(dominant)
 i: does not produce antigens
(recessive)
Type AB shows codominance, both
the A and B antigens are present on
the cell
Type O blood is homozygous recessive
Blood types
Genotypes
Phenotypes
IAIA or IAi
Type A
IBIB or IBi
Type B
IAIB
Type AB
ii
Type O
Blood Donation and Transfusions
You have to receive the right type of blood, or your
immune system will cause the cells to clump up
(agglutinate) and you will get very sick and this can
be fatal.
Type O is the Universal Donor, all blood types can
accept Type O blood
Type AB blood is the Universal Acceptor, as people
with blood type do not have an immune reaction to
any of the blood types
Blood Transfusions
Type A can accept Types A and O
Type B can accept Types B and O
Type AB can accept Types AB, A, B and O
Type O can ONLY accept Type O

Practice
A female with type AB blood has children
with a man who is heterozygous for type B
blood. What types of blood could their
children have?