1. Blood Types
Objective: Determine how blood types are inherited and how co-dominance applies to the ABO system

2. What Makes Up Blood?
RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our
blood; they are produced in the bone marrow and contain a protein
called hemoglobin that carries oxygen to our cells.
WHITE BLOOD CELLS (Leukocytes) –They are part of the immune
system and destroy infectious agents called pathogens.
PLASMA – This is the yellowish liquid portion of blood that contains
electrolytes, nutrients and vitamins, hormones, clotting factors, and
proteins such as antibodies to fight infection.
PLATELETS (Thrombocytes) – The clotting factors that are carried in
the plasma; they clot together in a process called coagulation to seal a
wound and prevent a loss of blood.

3. Genetics of Blood Your blood type is established before you are
born, by specific genes inherited from your
parents.
These two genes - one gene from your mother
and one from your father - determine your
blood type.

4. Who Has What Type? TYPES DISTRIBUTION RATIOS O + 1 person in 3 38.4%
7.7%
      A +
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:

5. Application to Medical Field
CAN RECEIVE
O -**
O +
B -
B +
A -
A +
AB - AB
Blood Types
AB+ X
O -

6. 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 = ____ AO AB AA BO BB
O O

7. Dominant & Recessive
O is recessive
A is dominant
B is dominant
What happens if A + B?

8. A B A B Co-dominance Since A & B are both dominant it is co-dominant
A new blood type results…AB

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

10. B O A O A A B O B O O O Example: Type A phenotype Type B phenotype
Dad has Type B blood type (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype. B O A O A A B ?
Type A phenotype
Mom has Type A blood because she has an A gene (red) and an O gene (yellow) O B O O O
Type B phenotype
Type O phenotype

11. Your Turn- Work it Out!
Complete a Punnett Square in your science notebook for each of the following practice exercises.
Write the genotype and phenotype in each quadrant of the Punnett Square.
You may use colored pencils. Red=A, Blue=B, Yellow=O

12. Exercise 1:
Dad has Type A blood (phenotype) because he has a A gene (red) and an O gene (yellow) A O O
Mom has Type O blood (phenotype) because she has an O gene (yellow) and an O gene (yellow) genotype. O

13. A O O A O O O O A O O O Answer Key 1:
Dad has Type A blood (phenotype) because he has a A gene (red) and an O gene (yellow) A O O A O O O
Type A phenotype
Type O phenotype
Mom has Type O blood (phenotype) because she has an O gene (yellow) and an O gene (yellow) genotype. O A O O O
Type A phenotype
Type O phenotype

14. Exercise 2:
Dad has Type A blood (phenotype) because he has a A gene (red) and an A gene (red) genotype A A A
Mom has Type AB blood (phenotype) because she has an A gene (red) and an B gene (blue) genotype . B

15. A A A A A A A A B A B B Answer Key 2: Type A phenotype
Dad has Type A blood (phenotype) because he has an A gene (red) and an A gene (red) genotype A A A A A A A
Type A phenotype
Type A phenotype
Mom has Type AB blood (phenotype) because she has an A gene (red) and an B gene (blue) genotype . A B A B B
Type AB phenotype
Type AB phenotype

16. 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

17. B B B B B B B B O B O O Answer Key 3:
Dad has Type B blood (phenotype) because he has a B gene (blue) and an B gene (blue) genotype B B B B B B B
Type B phenotype
Type B phenotype
Mom has Type B blood (phenotype) because she has an B gene (blue) and an O gene (yellow) genotype B O B O O
Type B phenotype
Type B phenotype

18. 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)

19. B A A A A B A B O A O O Answer Key 4: Type AB phenotype
Dad has Type AB blood (phenotype) because he has an A gene (red) and a B gene (blue) genotype B A A A A B A
Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow)
Type AB phenotype
Type A phenotype B O A O O
Type A phenotype
Type B phenotype

20. 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.

21. B O A B A O A B O O O O Bonus Answer Key:
Dad has Type B blood (phenotype) because he has a B gene (blue) and an O gene (yellow) genotype B O A B A O A
Mom has Type A blood (phenotype) because she has an A gene (red) and an O gene (yellow) genotype.
Type AB phenotype
Type A phenotype B O O O O
Type B phenotype
Type O phenotype

22. Optional Extension
Ask your parents if they know their blood type.
Ask your parents if they know your blood type.