NS 1011: Introduction to Biology

Blood Typing Lab

Introduction:

Blood type is determined by the presence or absence of specific antigens on the surface of red blood cells (erythrocytes).  There are two different classes of antigens: the A and B antigens, and the Rh antigens.  A person's blood type is determined by mixing blood with specific antisera which contain antibodies for the A, B, or Rh antigens.  If the blood agglutinates (clumps together) with a particular antiserum, then the blood contains that antigen.

Blood type is inherited through several different gene loci: the locus for the A or B antigens and the loci for the Rh antigens, of which there are several.  There are three different possible alleles for the A and B locus.  They are designated by the symbols I^A, I^B, and i.  A person with the I^A allele will produce the A antigen; a person with the I^B allele will produce the B antigen; the i allele produces no antigen.  The presence of any Rh allele will produce one of the Rh antigens.  These alleles combine to produce the different possible blood types: A⁺, A^-, B⁺, B^-, AB⁺, AB^-, O⁺, or O^-.

In this lab, we will be using simulated blood to determine the possible paternity of a child.  A recently divorced woman who is planning to remarry has discovered that she is pregnant.  Both the ex-husband and the fiancé are willing to take responsibility for the child, but they want to know which one of them is the father.  While blood typing cannot determine who is the father, it can eliminate people.

Materials

Four different simulated bloods:

• The mother's blood
• The child's blood
• Mr. Green's blood (the fiancé)
• Mr. Jones's blood (the ex-husband)

Three different antisera:

• Anti-A
• Anti-B
• Anti-Rh

Four sample plates
Toothpicks for stirring

Procedure

1. Label each sample plate
       Mother
       Child
       Mr. Green
       Mr. Jones
2. Place three to four drops of the Mother's "blood" in each of the wells of the sample plate labeled "Mother".
   Do the same for each of the other "blood" samples.
3. Place three to four drops of the simulated anti-A serum in each A well on the four sample plates.
4. Place three to four drops of the simulated anti-B serum in each B well on the four sample plates.
5. Place three to four drops of the simulated anti-Rh serum in each Rh well on the four sample plates.
6. Stir each well with a separate clean toothpick for 30 seconds.  To avoid splattering the simulated blood, do not press too hard on the sample plate.
7. Observe each slide and record your results.  To confirm agglutination, try reading text through the mixed sample.  If you cannot read the text, assume you have a positive agglutination reaction.

Conclusion Questions:

1. What is the blood type of each person?
2. Is it possible for Mr. Green to be the father?  Is it possible Mr. Jones to be the father?
3. Is it possible to tell the genotype for the A-B locus of each person? 
4. Give the genotype for each person for whom you can.

Lab report:

1. Title: A few words which make clear what the purpose of the lab was.
   Minus 1 point if no title
2. A brief introduction to the lab.  What was studied in this lab, and why did we study it?  Explain blood types.  Do not copy my introduction!
   3 points
3. Procedure: a brief description of each type of test.
   1 point
4. Data table.
   1 points
5. Conclusions: See conclusion questions above.
   4 points
6. Metacognitive analysis: A brief analysis of what worked in this lab and what didn't work, and why.  What contributed most to your learning?  What was confusing or unhelpful?  What would you change?
   1 point

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