1. Blood Types

2. Co-dominance
When two or more alleles for a gene contribute to the phenotype

3. Blood type alleles IA = type A marker (antigen)
IB = type B marker (antigen)
IO or just i = No markers (antigen)
Antigen – means marker on the surface of a cell
**antigens are how your body can identify which cells belong to you and which are foreign**

4. Antigens vs. Antibodies
Antigens (markers on your cells) are how your body recognizes which cells are yours and which cells are foreign.
Antibodies are what your body produces to fight off any cell that is not “marked” as yours.

5. THINK – PAIR - SHARE
If there are 3 co-dominant alleles, how many different blood types (phenotypes) are possible?
4 possible blood types A B AB O

6. Type A blood genotypes = IAIA or IAi
Has only A antigens on the surface
Has Anti-B antibodies A A A A A

7. Type B blood genotypes = IBi or IBIB
Has only B antigens on the surface
Has Anti-A antibodies B B B B B

8. Type AB blood genotype = IAIB
Has A and B antigens on the surface B A
No antibodies! A B B A A B

9. Type O blood genotype = IO IO or ii
Has NO antigens on the surface
Makes Anti-A and Anti-B antibodies

10. Fig

12. Rh Blood Group Rh positive indicates presence of antigen D
Rh negative indicates absence of Antigen D
Rh antigens, like A and B antigens are inherited and present from birth
Anti-D antibodies are not produced until after an individual is sensitized to antigen D

13. What blood can I receive?
Blood type:
Can receive from:
Can give to:
Type A
A or O
A or AB
Type B
B or O
B or AB
Type AB
A, B, AB or O
*UNIVERSAL RECIPIENT
AB only
Type O
O only
A, B and AB
*UNIVERSAL DONOR

14. What happens if the wrong blood type is given?