This investigative case module was prepared as part of a BioQUEST faculty development workshop. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
The Case: Trouble in Tucson: On the Horns of a Dilemma

Scenario part 1:

Wednesday: Doctor Yoshino’s office:

“Thank you so much for the great news, Dr. Yoshino! I can’t believe we’re going to have another little boy!” Maria exclaimed. “Alejandro and I are so happy! We’ve already decided to name him after my father, Javier.”

Alejandro echoed Maria’s excitement, but added “We can also be thankful that Leticia is such a healthy child, but we’re still so worried about little José. Even though they’re twins, he’s never had the energy that Leticia has. He seems breathless all the time, and his hands are swollen. He says his tummy hurts, and it seems swollen to us too. And you’ve had to treat him so often for infections.”

“I’d like you to talk to my colleague Dr. Marker”, Dr. Yoshino replied. She specializes in childhood disorders, and I’d like her to see José.”

Two weeks later: Doctor Marker’s office:

“I think I understand what you’re saying, Doctor.” Maria said. “You think that José’s symptoms might be due to this disease, sickle-cell anemia. But how will we know for sure?”

Dr. Marker explained, “We already discussed the fact that this disorder is genetic. There is a test that can be run. We can take DNA from José and compare it to DNA from people that we know have the disorder and people who don’t. Would you like me to order the test so we’ll know for sure?”

“I think we have to, Maria,” Alejandro replied, “at least then we’ll know what we need to do to care for José”.

With a quaver in her voice, Maria said “Dios mio! This is such a terrible situation. I can’t believe that José might have sickle-cell anemia. And what about our new baby? I couldn’t bear to watch more children suffer as José has – and it sounds like it might get worse. And you know that we had planned to have even more children – that seems so scary now. But I agree, let’s test José and then we’ll know for sure.”

Scenario part 2:

The following week: Doctor Marker’s office:

The doctor’s face was composed but sad when she said “I’m sorry to tell you that José’s test is positive. We’ll have to talk about some of the treatment options for him in a few minutes. But before we do that, did you have a chance to read the materials I gave you? Do you have any questions about them?”

“I’m even more confused about what we should do now. Does this mean that all of our kids might have this disease?” Alejandro asked. “I don’t know if we should have more kids if this might be their fate. What about Maria’s baby? Can we test him? What if we find out that Javier is going to get it? What would we do then?

Two years later in the Valenzuela’s kitchen:

“I can’t wait to go to see our family in Guatemala! We’ll have to remember to bring lots of bug spray, though; Manuel said that there are tons of mosquitoes there”, Maria told Alejandro.

“And there’s so many diseases there to watch out for too”, Alejandroagreed. “Didn’t the letter say your sister’s best friend was just diagnosed with malaria? Maybe we should make an appointment with Dr. Marker and find out if there’s something special we should do before we go.”

Case Author:
Julia Fiello Pima Community College
Jackie Smith Pima Community College

Case Analysis

In small groups, students will create a chart which includes the following information. Reporters in each group will share the information with the class.

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?

Learning Goals



  • Describe the principles of Mendelian Genetics; apply these principles to a genetic disorder.
  • Explain how biotechnology techniques can be used to test for some genetic diseases.
  • Explore ethical issues tied to reproduction and genetic disease.



Investigations and Activities

Complete the "corn genetics" labs (download the BIo 156 Lab 13 "Corn Genetics Lab" and Answer Key for Lab 13 - link to be loaded)
Complete two analyses of DNA (Jose only and whole family) using Case-It. (Case-It was created by Mark Bergland and Karen Klyczek, Biology Dept., University of Wisconsin, River Falls; Funding for the development of this project was provided by NSF and the project was initiated by the BioQUEST Curriculum Consortium.



Corn Lab (see Investigations and Activities)

Case-it program and guide (see Special Data Items)

Internet Resources



  • Harrison’s Principles of Internal Medicine 13th Ed., Isselbacher, Braunwald, Wilson, Martin, Fauci, Kasper, McGraw-Hill, 1994.
  • Pathology, 2nd Ed., Rubin and Farber, J.B. Lippincott Co., 1994

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

Sample run for complete family:

    1. mutated
    2. normal
    3. José
    4. Alejandro
    5. Maria
    6. Leticia
    7. Javier

1. corn3.jpg
2. dna2.jpg
3. electrophoresis4.jpg
4. family_results.gif
5. jose_results.gif
6. sickle_cell_blood.jpg
7. smallgroup.jpg
8. ultrasound.jpg


Student Products

Completed Corn lab

Case analysis and list of issues/problems (results from whole class)

Demonstration of José's genotype: "photo" of gel and explanation of results

Report - Sickle-cell Anemia genes in Valenzuela family which includes:

  • Hypotheses: genotypes or genotype options for each family member and rationale (might include Punnet squares)
  • Results:DNA restriction digest and Southern blot
  • Conclusions: confirmation of genotypes
  • Recommendations: risks for sickle-cell symptoms and malarial contraction

Position Paper (topic selected from list developed by class) which includes:

  • A clear statement of the issue/problem
  • Position supported with biological data
  • Acknowledgement/comment of alternative view (consensus positions shared after individual papers are written)

Assessment and Evaluation Plan

Pre-assessment: brief "quiz" to determine initial understanding of Mendelian Genetics concepts (0%)

Corn lab: student-graded using answer key; individual submission evaluated for completion and correction (10%)

Case analysis and Issues identification: "class" submission (0%)

Jose's genotype; small group submission evaluated for completion and correct determination (10%)

Report - Sickle-cell Anemia genes in Valenzuela family; instructor-graded evaluated using report rubric that assesses each of the components in the activity (insert link for a grading rubric sample; small group submission (30%)

Position paper: instructor-graded using grading rubric that includes communication style and ability to support the position (insert link for a grading rubric sample); individual submission (30%)

Post-assessment: quiz of unique problems to determine final understanding of Mendelian Genetics concepts; individual submission (20%)

Small group report of issues consensus (0%)



Day 1

  • The activity will begin with the instructor using the “Corn Genetics” lab to introduce the concept of Mendelian Genetics.
  • The instructor will describe how restriction enzyme digests and Southern blots can be used to identify variations in genes and demonstrate the use of the program Case-It with Huntington’s Chorea data.
  • The students will be given the initial phase of the case and will first work in small groups to identify what they know, what they don’t know, and identify issues that are raised in the first phase of the case.
  • A file of DNA that includes the “normal” and “affected” genes, the restriction enzyme MstII, and DNA from José will be given to each group, and they’ll use Case-It to digested the DNA, run it on a gel, probe for the affected gene and determine José’s genotype. The instructor will act as a guide to ensure that each group understands how the program works.
  • For homework, the students will review their prior notes from their earlier lab on sickle-cell anemia (protein lab) and determine how sickle-cell in inherited. They’ll also research the connection between mosquitoes, malaria and sickle-cell trait and sickle-cell anemia.

Day 2:

  • The small groups will share what they’ve learned, and the reporter in each group will share key aspects of the research with the class.
  • The groups will be asked to identify the genotypes or genotype possibilities for each family member (their hypotheses).
  • They’ll then be given disks that include DNA for the whole family, and will be asked to create a report for the doctor that demonstrates the genotype for each family member, and also each person’s risk for malaria.
  • The group reporter will share the results with the class.
  • For homework, each student will select one of the issues from the list and write a position paper that demonstrates understanding of both sides of a complex issue.

Day 3

  • The students who selected the same issue/problem will work for a brief period in small groups. A reporter will describe the group's consensus to the class.

Course name:
Biology 156: Human Biology for Allied Health (covers cell and molecular biology and histology; preparation course for Anatomy and Physiology; course description and objectives; sample Bio156 Course Syllabus and Schedule
Likely sequence in syllabus:
After cell organelle structure and function; cellular division (mitosis and meiosis), after DNA and protein synthesis
Time during term:
Week 14 of 16
2 classes
Lab (outside of class requires computer access for research)
Students in course:
Collaborative elements:
Work individually, in small groups and with whole class ;
Additional notes:



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