Blood Typing
Blood Typing
 Blood
is made of fluid (plasma) and solids
(cells)
 The red blood cells (corpuscles or
erythrocytes) may have certain proteins on
their coats called antigens.
 The plasma may carry proteins that attack
foreign antigens. These are called
antibodies.
Type
Antigen
Antibody
A
α
β
Alleles
(genes,
genotype)
AA AO
B
β
α
BB
O
_____
α+β
OO
AB
α+β
____
AB
BO
 If
two different blood types are mixed
together, the blood cells may begin to
clump together in the blood vessels,
causing a potentially fatal situation.
Universal Donor and Receiver
 In
an emergency, type O blood can be
given because it is most likely to be
accepted by all blood types (universal
donor). It has no antigens. However, there
is still a risk involved.
 Type AB is a universal receiver because it
has both A and B antigens already.
 If
blood cells are carrying antigen (α)
proteins on their surface, they will form
clumps (AGGLUTINATE) when mixed with
antibody (- α), this is A. B blood will also
form clumps, however it has to be mixed
with (-β).
 In
type O blood there is no evidence of
clumping because neither antigen (α) or
antigen (β) are present.

A homozygous A
blood crosses with a
heterozygous B
blood. What are the
possible blood types
of the offspring?
F1
A
A
B
AB
AB
O
AO
AO
AA x BO
2/4 have type AB blood
2/4 have type AO blood (heterozygous A)
A heterozygous type
A blood crosses with
a heterozygous type
B blood, give
frequencies of
possible offspring
blood types.
AO x BO
1 type AB blood
1 type BO blood
1 type AO blood
1type OO blood
F1
A
O
B
AB
BO
O
AO
OO
A type O crossed with
type AB, find
frequencies of
possible offspring
blood types.
OO x AB
½ type AO blood
½ type BO blood
F1
O
O
A
AO
AO
B
BO
BO
Rhesus Factor
 Sometimes
human blood clumps
(agglutinates) when mixed with serum from
the Rhesus monkey blood. This is called
RH+ (the human blood cells are carrying
antigen D).
 A problem can occur when you have a RH+
father and a RH– mother.
A problem can occur when you have a RH+ father
and a RH– mother.
 RH– blood carries antibodies D.
 During the birth of the first RH+ child the maternal
and fetal blood mix so that the mother develops a
concentration of antibodies D.
 At the birth of a second RH+ child, the maternal
blood that enters the fetal system attacks the
antigens D causing agglutination, as a result, the
brain is deprived of oxygen and it may result in
some form of mental retardation.

The female has 2 X
F1
chromosomes (XX)
and the male has an
X and Y chromosome
(XY). What re the
X
percentage chance of
having a boy or girl?
Y
XX x XY
50% girl
50% boy
X
X
XX
XX
XY
XY