Transcript Multiple alleles

Most genes have more than two alleles for the same character
MULTIPLE ALLELES
ABO BLOOD GROUPS
Involves three alleles for a single
gene.
 These three genes, in various
combinations, produce four
phenotypes.
 Type A, B, AB, O

Carbohydrate A & B
ABO BLOOD GROUPS

A and B refer to carbohydrates
that are found on the surface of
the red blood cells that bind to
antibodies.
O
- no carbohydrates
 A - carb. A
 B - carb. B
 AB - carbs. A and B
ABO BLOOD GROUPS

The four blood types result
from various combinations
of the three different
alleles symbolized as:
 IA
– A is codominant to B
 IB – B is codominant to A
 ii – O is recessive
* Alleles IA & IB are codominant.
BLOOD TYPING PROBLEM

If the mother has heterozygous type A blood
and the father has heterozygous type B blood,
is it possible for the child to have type O blood?
ABO BLOOD GROUPS

Each blood type has antibodies which bind to
foreign carbohydrates (causing the blood to
clump).
 This

reaction is a part of the immune system.
Example: Type A blood has antibodies that
react with carbohydrate B.
ABO BLOOD GROUPS

Matching compatible blood groups is important
for safe blood transfusions.

Type A blood can accept: A or O
ABO BLOOD GROUPS

Matching compatible blood groups is important
for safe blood transfusions.

Type B blood can accept: B or O
ABO BLOOD GROUPS

Matching compatible blood groups is important
for safe blood transfusions.

Type AB blood can accept: A, B, or O
ABO BLOOD GROUPS

Matching compatible blood groups is important
for safe blood transfusions.

Type O blood can accept: O only
ABO BLOOD GROUPS

Matching compatible blood groups is important
for safe blood transfusions.

Type O blood is known as the universal donor.

Type AB blood is known as the universal
recipient.