1. Human Blood Groups- Multiple Alleles AND CoDominance
OK… Humans and many other primates

2. Recall: There are three different alleles for human blood type (multiple alleles):IA A IB B i O
“A” indicates the presence of 1 type of antigen (protein that can “activate” your immune system) and “B” represents a different antigen on the surface of a red blood cell
“O” has no antigen on the surface of the RBC

3. Blood types of offspring (Phenotype)
Allele from Parent 1
Allele from Parent 2
Genotype of offspring
Blood types of offspring (Phenotype) A AA O AO B BB BO AB OO

4. Antibodies
A “foreign” antigen will trigger your immune system to create antibodies.
Since antibodies are proteins, they have a specific shape & will attach onto the antigen for which they were made.
There are bacteria in the atmosphere that have a very similar shape to our “A” and “B” antigens & we are exposed to them as soon as we are born.

5. Therefore, each person can have antibodies against an antigen they didn’t inherit.
These antibodies are floating around in our blood with our RBC’s.

6. Type A blood (has A antigens on cell surface) has Anti-B antibodies
Antibodies are named for what they attack
Anti-B antibodies attack and will clump up (agglutinate) in the presence of B-antigen
Type B blood (has B antigens on cell surface) has A-antibodies

7. Type AB blood doesn’t have any antibodies
Type O blood has Anti-A and Anti-B antibodies

9. Rh Factor
The Rh factor genetic information is also inherited from our parents, but it is inherited independently of the ABO blood type alleles (a separate gene).

10. There are 2 different alleles for the Rh factor known as Rh+ and Rh-.
Normal dominant/recessive inheritance
Positive (+) allele is dominant to negative (-) allele
Rh +: you have the protein Rh-: you don’t
Mother
Father
Child
Rh-
Rh+

13. The “Rh Issue”… Mom = Rh- Baby #1 = Rh+

14. Reactions w/ Anti-A Serum Reactions w/ Anti-B Serum
Blood Typing Test
Reactions w/ Anti-A Serum
Reactions w/ Anti-B Serum
Blood Type
Agglutination (+)
No Agglutination (-) A B AB O
We will be determining blood types using Anti-A serums, Anti-B serums, and Anti-RH serums. Use the chart to help you determine the blood type of each sample and its Rh factor (+ or -).
Agglutinins = Antibodies
Rh Serum - Clumping = Rh+ blood
Directions:
Step 1: Lay out a typing tray and three toothpicks from your kit on a paper towel.
Step 2: Place 2 drops of the blood sample in each well on the typing tray.
Step 3: Place 2 drops of the anti-A serum on the blood in the A well.
Step 4: Place 2 drops of the anti-B serum on the blood in the B well.
Step 5: Place 2 drops of the anti-Rh serum on the blood in the Rh well.
Step 6: Use three clean toothpicks to stir the serum into each sample for 30 seconds.

15. Agglutination = Clumping
Step 7: Record your observations in the correct section on the back of your worksheet and use the reaction chart on the front page to determine the blood type.
Step 8: Complete the other sections using information from your classmates.
No clumping
Clumping
Agglutination = Clumping
What is this person’s blood type?
Answer: B+