Blood Types & Inheritance

Dr. Charles Drew• Today's American Red Cross

blood program is the result of the efforts of Dr. Charles R. Drew, a blood specialist, surgeon, educator and scientist.

• His pioneering work in blood collection, plasma processing and transfusion laid the foundation for modern blood banking.

What are antigens & antibodies?• The differences in human blood are due to protein

molecules called antigens and antibodies. • The antigens are located on the surface of the red blood

cells’ plasma membrane. • The antibodies are in the blood plasma (liquid).

– Antibodies are used to identify/destroy foreign blood cells.

                 

     

 

What are the different blood groups?• Individuals have different types and

combinations of antigens and antibodies.

What happens when different blood types are mixed?

• Not all blood groups are compatible with each other.

• Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.

• This can lead to death

How is blood type genetically determined?

• The ABO genes are determined by multiple and co-dominant alleles.

• There are three different alleles for human blood type: IA ,IB , & I

• Since there are 3 different alleles, there are 6 different possible genotypes and 4 different possible phenotypes.

Phenotype/Phenotype/Blood TypeBlood Type GenotypeGenotype MeaningMeaning

OO

Aa or AOAa or AO

BB or BOBB or BO

ABABA & B antigens are A & B antigens are

presentpresent

OONeither A nor B

antigens are present

AOnly the A antigen is

present

BOnly the B antigen is

present

AB

Phenotype/Phenotype/Blood TypeBlood Type GenotypeGenotype MeaningMeaning

OO

IIAAi or Ii or IAA I IAA

A & B antigens are A & B antigens are presentpresent

iiNeither A nor B

antigens are present

AOnly the A antigen is

present

B IBi or IB IB Only the B antigen is present

AB IAIB

Blood Transfusions - who can receive blood from whom?

• The transfusion will only work if the recipient does not produce antibodies for the donor’s blood type.

Blood Blood TypesTypes

Can donate Can donate blood toblood to

Can receive Can receive blood fromblood from

ABAB ABAB AB, A, B, OAB, A, B, O

AA A & ABA & AB A & OA & O

BB B & ABB & AB B & OB & O

OO AB, A, B, OAB, A, B, O OO

• The Universal Donor can donate blood to a person any blood type.

• Which blood type is the Universal Donor? O-

• The Universal Recipient can receive blood from any blood type.

• Which blood type is the Universal Recipient? AB+

Population Distribution of Blood Types in the U.S.

Type Percent

O

A

B

AB

45

40

11

4

Practice Problems!

Give the genotype & phenotype ratios for the following crosses:

1. IAIA x IBiGenotypes: 1 IAIB : 1 IAi

1. Phenotypes: 1 AB : 1 A

2. Type O x Type ABGenotypes: 1 IAi : 1 IBiPhenotypes: 1 A : 1 B

At the hospital, 2 newborn babies were accidentally mixed up and the parents questioned which baby belonged to whom. The blood groups of everyone involved are listed below. Determine which baby belongs to which couple.Baby 1 – Type A Mr. Brown – Type ABBaby 2 – Type O Mrs. Brown – Type B

Mr. Smith – Type BMrs. Smith – Type B

Who’s Baby is it?

Who’s baby is it? answer…

• Baby 1 has to belong to Mr. & Mrs. Brown. There is no way that they could create a Type O (ii) baby when only one parent could possibly contain the i allele.

• Baby 2 has to belong to Mr. & Mrs. Smith. There is no way that they could create a Type A (IA IA, IAi) baby with out either carrying the IA allele.

Which child is adopted?• The Tyler family has three kids, one of which is

adopted. The blood types of the parents and children are listed below. Determine which child is adopted.

Mom -Type AB John- Type B

Dad- Type O Martha- Type AB

Zackary- Type A

Which child is adopted? ANSWER

Martha (IAIB) is adopted because Dad is Type O (ii) and could not have given either of her two alleles.

Genetics and Biotechnology TEST Study Guide

• Be familiar with the following terms, homozygous, heterozygous, phenotype, genotype, pure bred, and hybrid.

• Know how to solve genetics problems.• Know the purpose of a test cross.

• Be familiar with the following terms: selective breeding, genetic engineering, cloning, DNA fingerprinting.

• Know how to read a karyotype. • Be able to do sex linkage problems and

blood group problem• Know how to read a pedigree(we will do

this when I return)