Human Blood Types

• A person’s blood type is controlled by the genes they inherit from their parents.

• The combination of genes inherited controls what protein/antigens are found on a person’s red blood cells.

• There are four different genes that control what blood type a person has.• Gene A• Gene B Chromosome 9• Gene O

• Gene Rh Chromosome 1

• These 4 genes code for 3 different proteins/antigens.• Gene A codes for the A antigen• Gene B codes for the B antigen• Gene O codes for no antigen (zero)• Gene Rh codes for the Rh antigen

• The presence or absence of these antigens determine which of the 8 different blood types a person has inherited.• A+

• Has the A and Rh antigens• A-

• Has the A antigen• B+

• Has the B and Rh antigens• B-

• Has the B antigen

• AB+• Has the A, B and Rh antigens

• AB-• Has the A and B antigens

• O+• Has the Rh antigen

• O-• Has no antigens.

• What blood type is known as the universal donor and why?

• O-• Has no antigens so there is nothing for the recipient to reject.

• What blood type is known as the universal recipient and why?

• AB+• Has all three antigens so no matter what blood they receive they will

recognize and accept it.

Agglutination:• When two different blood types mix and

they contain different antigens, the blood will clump or agglutinate.

• Can A+ blood (A and Rh antigen) be transfused into a person with B+ blood (B and Rh antigen)?

Phenotypes and Genotypes:

• A blood• AA or AO

• B blood• BB or BO

• O blood• OO

• AB blood• AB

Rh+ blood Blood with Rh antigen

Rh- blood Blood with no Rh antigen

Rh + is dominant over Rh-

Rh+ and Rh+ = Rh+ blood

Rh+ and Rh- = Rh+ blood

Rh- and Rh- = Rh- blood

• Lets start simple:• Cross a women with AA blood with a man

with AB blood. What would be the genotypic and phenotypic ratio of the offspring?

• A little more challenging…..

• Cross a women with AB- blood with a man who as OO+ blood. Determine both the genotypic and phenotypic ratios of the offspring.