MULTIPLE ALLELES

Most genes have more than two alleles for the same character

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.