Genetics of Blood Types

 

Subject Area

 Biology - Physiology

Age or Grade

 Introductory Biology – Grades 9 +

Estimated Length

 1 hour

Prerequisite knowledge/skills

 Students should be familiar with basic concepts in genetics and immunity: heredity, gene, allele, dominant, recessive, antibody, immune system. Ideally, students will also come to class knowing their own blood type.

Description of New Content

 This activity analyzes the differences in blood types, and demonstrates the genetic basis of blood typing

Goals

Materials Needed

Per group of students (3-4 people per group)

1)      2 plastic straws (no bendable joints)

2)      2 small balloons

3)      1 large balloon

4)      Rubber cement

5)      2 small rubber bands

6)      1 large rubber band

7)      Empty 2 liter plastic bottle

8)      Scissors

9)      Modeling clay

Procedure

 

 

 

1)      Antigens, antibodies, and transfusions

a.       The teacher will conduct an introductory lecture or ppt presentation on the basic biology of blood types, covering the following contents:

                                                         i.      Red blood cells contain different antigens on their surface (A, B, or none)

                                                       ii.      The presence of a foreign antigen in the body will make the immune system produce antibodies to the antigen, and release them into the blood stream

                                                      iii.      Antibodies against A antigens will cause type A red blood cells to clump and coagulate. Thus, individuals with type A blood cannot receive type B and visa versa

                                                     iv.      Blood type AB consists of red blood cells with both A and B antigens, while blood type O blood cells have no antigens.

b.      Students will divide into groups to complete the Transfusion Compatibility worksheet.

2)      Inheritance of blood type

a.       The teacher will conduct a second lecture on how blood types are inherited, covering the following concepts:

                                                         i.      Blood type is inherited from both parents, where mother and father contribute one allele each to the offspring.

                                                       ii.      When the offspring inherits two different alleles for blood type, the resulting phenotype will be some combination of the father’s antigens and the mother’s antigens.

                                                      iii.      People with blood type AB have an allele for A and B antigens. People with blood type A (or B) have an allele for A (or B) antigen, and an allele for “no antigen”. People with blood type O have two alleles for “no antigen”

                                                     iv.      Example 1: Mother = AB, Father = AB, offspring can be A, AB, or B.

                                                       v.      Example 2: Mother = AB, Father = A, offspring can be A, or AB. The offspring cannot be B its blood type must contain information from the mother AND the father.

                                                     vi.      Example 3: Mother A, Father O, offspring can be A or O because the offspring can receive the allele for “no antigen” from the father and an allele for A or “no antigen” from the mother.

b.      Students divide into groups and complete the “Blood Type Inheritance” work sheet.

Evaluation

Students will be evaluated on class participation and given a group grade based on the completion and accuracy of their worksheets.

Extensions

  Transfusion Compatibility worksheet, Blood Type Inheritance worksheet,

References

“Modern Biology” Textbook, Wikipedia