Download Blood Types - Fort Bend ISD

Jumpstart 12/3
A pea plant with the genotype TtWW is
crossed with a pea plant with the genotype
ttWw. How many different genotypes can
be expressed in the offspring? _____
(SHOW ALL WORK!)
a. 1
b. 2
c. 3
d. 4
How many different phenotypes? ______
Blood Types
Multiple Alleles
More than two forms of a gene that code
for a trait (more than 2 letters to represent
the trait)
 Phenotype is still determined by a pair of
alleles! The gene pool simply contains
more than two.
 These alleles can be expressed in various
ways:

 Complete
dominance
 Co-dominance
 Incomplete dominance
Multiple Alleles: Human Blood Type
Blood Type is Coded by Multiple Alleles A, B, and O.
*A and B are co-dominant.
*A and B are completely dominant over O.
Genotypes
AA
AO
BB
BO
AB
OO
Phenotypes
Type A
Type A
Type B
Type B
Type AB
Type O
*The genes cause the production of a cell surface protein A or B.
Type O cells have neither protein, so Type O individuals are
Universal DONORS. Which individuals are Universal RECEPIENTS
(have both proteins)?
Blood Types…

Blood from the donor to the recipient must
be compatible.

The problem occurs when the protein
(antigen) outer layer of the RBC of a donor
becomes coagulated (clumped) with the
plasma proteins (antibodies) of the
recipient.
Blood Types…

There are four different types of blood
 A,
B, AB, O

They are determined by the protein (antigen)
found on the RBC

Type A, has protein (antigen) A on the RBC
Type B, has protein (antigen) B on the RBC
Type AB, has both protein (antigen) A and B on
the RBC
Type O, has neither protein (antigen) on the
RBC



 Type
A would have B agglutinins
(antibody) in the plasma.
 Type B would have A agglutinins
(antibody) in the plasma.
 Type AB would not have agglutinins
(antibody) in the plasma.
 Type O would have A and B
agglutinins (antibody) in the plasma.

Type O is the universal donor, since it
does not have antigens (proteins) on the
surface of the RBC’s
 It
can be given to anyone and no clumping will
occur!

Type AB is the universal recipient, since it
does not have agglutinins (antibody) in its
plasma.
 They
can receive any blood since they have
no antibodies!
Multiple Alleles
Many genes are present
in 3 or more versions
(alleles) – this is known
as multiple alleles.
The human ABO blood group
is determined by three alleles
(IA, IB, and i) of a single gene.
The AB phenotype
(genotype IA IB) is an
example of
codominance!!
Codominance
The human ABO blood group
illustrates another genetic
phenomenon – codominance.
Codominance occurs when
the phenotype associated with
each allele is expressed in the
heterozygote – both are
expressed!
Problem 1
1. In humans, the blood types A, B, AB and
O are determined by three alleles. A man
who has AB blood marries a woman with
O blood. What are the genotypes and
phenotypes of the offspring?
Problem 2
2. A man who is heterozygous type A
marries a woman who is heterozygous
type B. What percentage of their offspring
will be Type 0?
Problem 3
3. If a man with blood type B, one of whose
parents had blood type O, marries a
woman with blood type AB. What
percentage of their children should have
blood type B?
Problem 4
4. A man with type O blood and a woman
with type AB blood get married. One of
their children needs an operation. This
child has type B blood. Can the child
safely receive a blood transfusion from
either parent? If not, why?
TOTD -Multiple Alleles:Who’s the
baby daddy?
You have been hired by Maury Povich to work for a show he is
Having on
1
2
Baby A - Type O Blood
Baby B - Type B Blood
Smiths - Types O and AB
Jones - Types A and B
Baby C - Type AB Blood
Baby D - Type A Blood
Squares -Types AB and AB
Angles -Types AB and O