Objective: Determine how blood types are inherited and how co-dominance applies to

the ABO system

Blood Types

Genetics of Blood

•Your blood type is established before you areborn, by specific genes inherited from yourparents.

•These two genes - one gene from your motherand one from your father - determine yourblood type.

Who Has What Type?TYPES     DISTRIBUTION RATIOS

      O + 1 person in 3 38.4%

      O - 1 person in 15 7.7%

      A + 1 person in 3 32.3%

      A - 1 person in 16 6.5%

      B + 1 person in 12 9.4%

      B - 1 person in 67 1.7%

     AB + 1 person in 29 3.2%

     AB - 1 person in 167 0.7%

source: http://www.bloodbook.com/type-facts.html

Application to Medical Field  CAN RECEIVE

   

O -** O + B - B + A -

A + AB - AB

Blo

od

Typ

es

AB+ X X X X X X X X

AB - X   X   X   X  

A + X X     X X    

A - X       X      

B + X X X X X      

B - X   X          

O + X X            

O - X              

Genotypes & Phenotypes•There are 4 different types of blood:

A, B, AB & O.

•Blood types (phenotypes) are determined by the following allele or gene combination (genotype):

Give the genotype(s) for each blood type.Type A = ____ ____ Type AB = ____Type B = ____ ____ Type O = ____

AA AO

BB BO

AB

O O

Dominant & Recessive

• O is recessive

• A is dominant

• B is dominant

• What happens if A + B?

Co-dominance

B ASince A & B are both dominant it is co-dominant

A B A new blood type results…AB

Example: Dad has Type B blood type (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype.

Mom has Type A blood because she has an A gene (red) and an O gene (yellow)

B OO

B

B

A A A OO

OOOOOOOO

Example: Dad has Type B blood type (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype.

Mom has Type A blood because she has an A gene (red) and an O gene (yellow)

B OO

B

B

A A A OO

OOOOOOOO

Type A phenotype

Type O phenotypeType B phenotype

?

Exercise 1:

Dad has Type A blood (phenotype) because he has a A gene (red) and an O gene (yellow)

Mom has Type O blood (phenotype) because she has an O gene (yellow) and an O gene (yellow) genotype.

OOA

OO

OO

Answer Key 1:

Dad has Type A blood (phenotype) because he has a A gene (red) and an O gene (yellow)

Mom has Type O blood (phenotype) because she has an O gene (yellow) and an O gene (yellow) genotype.

OOA

OO

OO A

A

OO OO OO

OO OO OO

Type A phenotype

Type A phenotype

Type O phenotype

Type O phenotype

Exercise 2:

Dad has Type A blood (phenotype) because he has a A gene (red) and an A gene (red) genotype

Mom has Type AB blood (phenotype) because she has an A gene (red) and an B gene (blue) genotype .

A A

A

B

Answer Key 2:

Dad has Type A blood (phenotype) because he has an A gene (red) and an A gene (red) genotype

Mom has Type AB blood (phenotype) because she has an A gene (red) and an B gene (blue) genotype .

A A

A

B

A A A A

A AB B

Type A phenotypeType A phenotype

Type AB phenotype Type AB phenotype

Exercise 3:Dad has Type B blood (phenotype) because he has a B gene (blue) and an B gene (blue) genotype

Mom has Type B blood (phenotype) because she has an B gene (blue) and an O gene (yellow) genotype

Answer Key 3: Dad has Type B blood (phenotype) because he has a B gene (blue) and an B gene (blue) genotype

Mom has Type B blood (phenotype) because she has an B gene (blue) and an O gene (yellow) genotype

BB B

B B

B B

BBOO OO OO

Type B phenotype Type B phenotype

Type B phenotype Type B phenotype

Exercise 4: Dad has Type AB blood (phenotype) because he has an A gene (red) and a B gene (blue) genotype

Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow)

Answer Key 4: Dad has Type AB blood (phenotype) because he has an A gene (red) and a B gene (blue) genotype

Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow)

A

A B

B

B

A A A

OO OO OOA

Type AB phenotypeType A phenotype

Type A phenotype Type B phenotype

Bonus Exercise:

Dad has Type B blood (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype

Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow) genotype.

Bonus Answer Key:

Dad has Type B blood (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype

Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow) genotype.

A A A

B

OO OOOO OO

OO

OOB

B

Type AB phenotype Type A phenotype

Type O phenotypeType B phenotype

Optional Extension

• Ask your parents if they know their blood type.

• Ask your parents if they know your blood type.