Multiple Alleles BLOOD TYPES An application of Codominance

Multiple Alleles: BLOOD TYPES An application of Co-dominance Mode of Inheritance

Review: Co-dominance: Two dominant alleles are expressed at the same time.

CODOMINANCE…MULTIPLE ALLELLES n Some traits have more than two alleles. For blood types, 2 of the genes are codominant and one is recessive. n 3 possible genes: n n. A and B are codominant n O is recessive. n Genes: A = IA B = IB O=i

The Story of Blood Transfusions… n Mid-1700’s: n n 1795: n n An English physician transfused sheep’s blood into a wounded soldier. The soldier died a painful death. Philadelphia physician Philip Syng Physick performed the first human-to human blood transfusion (not published). 1881: n First recorded human-to-human blood transfusion by British physician James Blundell. Patient shows initial improvement and then dies.

1901: n Austrian physician Karl Landsteiner discovers the three main human blood groups (A, B and C…he later changed C to O). For this, he was awarded the He mixed red blood cells with Nobel Prize. n n n different kinds of blood. When he mixed “A” blood with red blood cells from the “B” group, he saw clumping. The same thing happened when he did the opposite. He found that when he put red blood cells from group “C” into any other blood type, there was never any clumping.

n n 1902: n Dr. Alfred von Decastello and Adriano Sturli identify “AB” blood type which clumps in both “A “ and “B” blood. n This clumping is called “agglutination. ” 1907: n Dr. Reuben Ottenberg, New York, performs the first transfusion using cross matching (matching blood types). n Over the next several years, he virtually eliminates transfusion reactions. n 1917: n Dr. Oswald Robertson collects and stores type O blood to be used for casualties in World War I. n This would be the first blood “bank. ”

Picture of Red Blood Cells

ANTIGEN (Agglutinogen-kind of protein) n n n On the surface of the cell membrane of a red blood cells, there are proteins protruding out. These proteins are called “antigens” or “agglutinogens. ” They are used to identify the cells as “self. ”

n Antibodies: Your bodies defense mechanism. Antibodies attack foreign substances. n If the wrong blood type is transfused into a person (such as ‘A’ into an ‘O’ person), the antibodies in the recipient’s blood will try to destroy the group A cells. n

Why, when you mix certain people’s blood, does it cause clumping: n n Example: Anti. A antibodies attach to A antigens, binding red blood cells together and causing clumping. The kidney tries to filter the clumps out of the blood and the kidneys can become damaged to the point of kidney failure.

Blood Type Genotype(s) Antigens A B AB O Antibodies

Blood Type Genotype(s) Antigens A B AB O IAIA or IAi Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi B IBIB or IBi AB O Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi B IBIB or IBi AB IA IB O Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi B IBIB or IBi AB IA IB O ii Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi B IBIB or IBi AB IA IB O ii Antibodies Anti-B Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi B B I I or I i AB IA IB O ii Antibodies Anti-B Antibodies Anti-A Antibodies

Blood Type Genotype(s) Antigens A IAIA or IAi Antibodies Anti-B Antibodies B I I or I i Anti-A Antibodies AB IA IB No Antibodies O ii B B B

Blood Type Genotype(s) Antigens A IAIA or IAi Antibodies Anti-B Antibodies B I I or I i Anti-A Antibodies AB IA IB No Antibodies O B B B ii Both Anti-A and Anti-B Antibodies

• Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? Gametes

• Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) Gametes

• Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) Gametes IA IA Gametes

Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) Gametes i i IA IA Gametes

Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) IA IA i IAi Gametes

Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) IA IA i IAi Gametes IA i

Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) IA IA i i IAi i Gametes IA i

Example Cross a type A father and a type O mother. One of their children is a type O. Is this child adopted? (2 possible punnett squares) IA IA i Gametes IA i ii IAi i IA i ii

UNIVERSAL DONOR VS UNIVERSAL RECIPIENT n n What type of blood would be the Universal Donor and why? Type O because it has no antigens on its surface to be recognized by antibodies. What type of blood would the Universal Recipient and why? Type AB because it has no antibodies to recognize and attack foreign blood types.

Rh Factor n Rh positive: indicates the presence of the Rh antigen on the red blood cell. n n n This is dominant. “+ + or + -” Rh negative: indicates the lack of Rh antigen on the surface of the red blood cell. n n This is recessive. “- -”

Anti-Rh Antibodies n A person only develops anti-Rh after exposure to Rh-positive cells through transfusion or pregnancy. n n n Leakage of red blood cells from an Rh+ baby into a Rh- mother’s system during delivery will cause a build up of the anti-Rh antibodies in the mother’s blood. This takes awhile so probably won’t affect the first baby. The anti-Rh antibodies can pass through the placenta and enter the circulatory system of the next Rh+ baby. n This will clump the baby’s red blood cells.

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? Gametes

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? (2 possible punnett squares) Gametes

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? (2 possible punnett squares) Gametes + + - - Gametes

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? (2 possible punnett squares) Gametes - - + +- +- Gametes

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? (2 possible punnett squares) Gametes - - Gametes + +- +- + + +- +- -

Example: Cross a type Rh+ father and a Rh- mother. What is the chance that their baby will cause a build up of anti-Rh antibodies in the mother? (2 possible punnett squares) Gametes - - IA IA + +- +- IAi - -- -- - - + IA IA + IA i

n n Most common blood types: n A+ and O+ n make up about 72% of the population. Least common blood type: n AB- n make up only about 1% of the population