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

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

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

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.

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.

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

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

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).

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+

                                                                                      

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

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.

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+