Most genes have more than two alleles for the same character

 Involves three alleles for a single gene.  These three genes, in various combinations, produce four phenotypes.  Type A, B, AB, O Carbohydrate A & B

 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

 The four blood types result from various combinations of the three different alleles symbolized as:  I A – A is codominant to B  I B – B is codominant to A  ii – O is recessive * Alleles I A & I B are codominant.

 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?

 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.

 Matching compatible blood groups is important for safe blood transfusions.  Type A blood can accept: A or O

 Matching compatible blood groups is important for safe blood transfusions.  Type B blood can accept: B or O

 Matching compatible blood groups is important for safe blood transfusions.  Type AB blood can accept: A, B, or O

 Matching compatible blood groups is important for safe blood transfusions.  Type O blood can accept: O only

 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.