Ch. 14 and Section 37.2

Blood Type

A. Blood Group GenesA. Blood Group Genes1. Antigens/antibodies1. Antigens/antibodies2. Genes are responsible 2. Genes are responsible for humanfor human blood blood groups groups

a. ABO blood groupsa. ABO blood groupsb. Rh blood groupsb. Rh blood groups

I. Human Genes and our I. Human Genes and our BloodBlood

Blood Group Terms

Antigens: chemical structures imparting specific properties to the surface of the RBC

Antibodies: protein substance developed in response to foreign body substances

•ABO blood group–There are 3 alleles for this gene, IA, IB, and i.

–Alleles IA and IB are codominant.ABO Blood Group is results in 3 phenotypes:.Type AType BType O

Co-Dominant

Recessive

Blood types: Type A, B, or O?

If your genotype is IAIA, your phenotype is ______________

If your genotype is IBIB, your phenotype is ______________

If your genotype is IAi, your phenotype is ______________

If your genotype is ii, your phenotype is ______________

If your genotype is IAIB, your phenotype is ______________

Let’s do a Punnett Square….

Cross a heterozygous type A mom with a recessive dad. Give the possible genotypes and phenotypes of the offspring.

Genotype:

Phenotype:

Blood cells have either “A or B” antigens on outside surface of blood cell or NO antigens, which gives you blood type “O”.

The Rh FactorRh Factor – type of protein on the

surface of Red Blood CellsIf the Rh antigen is also present, the person is Rh+, if he/she does not have it, they are Rh-

Rh blood group is determined by a single gene with two allelesPOSITIVE [Rh+, Rh+] or {Rh+, Rh-] (Dominant)

NEGATIVE [Rh-, Rh-] (Recessive)

Blood Typing The presence or absence of 3 specific surface

antigens (A, B & Rh) determine your “blood type”

Your surface antigens are recognized by your immune defense system as “self”.

Plasma antibodies are responsible for “protecting” you from an incompatible blood type.

Anti-Rh antibodies are not “automatically” made by Rh- people

Blood Typing

Your blood cells have surface antigens based on your blood type

Your plasma makes antibodies against the antigens you don’t have

Human Genes

The i allele is recessive. Individuals with alleles IAIA or IAi produce only the A antigen, making them blood type A.

Fig. 14-4 page 344

Human Genes

Individuals with alleles IA and IB produce both A and B antigens, making them blood type AB.

Human Genes

Individuals who are homozygous for the i allele (ii) produce no antigen and are said to have blood type O.

WRONG BLOOD TYPE???If given the

“wrong” blood type for medical purpose, the immune system would recognize the blood cells as foreign and destroy them!

Rh Incompatibility

When Rh– person receives Rh+ blood in a transfusion person develops antibodies against the Rh+ factor

Clinical problem if second transfusion of Rh+ blood given Rh antibodies will clump with the Rh antigens

S/S of transfusion reaction: chills, fever, rash, itching, SOB, nausea, nephralgia, hematuria, shock & death

We say the universal donor is Type ____ and the universal recipient is Type ______. However, Rh factor does matter!!!