As easy as one, two, pee: A study of Alkaptonuria

Overview & Concepts

This lesson introduces students to the Orina family.  Carlos, a member of the Orina family, has been diagnosed with a genetic disease called Alkaptonuria, which makes a person's urine turn dark black.  During this lesson, students first take on the role of a geneticist and use the OMIM database to prepare a one-page summary sheet that could be presented to the Orina family with information about the disease.  Students then perform a lab in which they test urine samples from other members of the family for the presence of Alkaptonuria.  Students then construct a family pedigree and use their knowledge of modes of inheritance to help counsel the remaining family members about their disease.

Grade Level: 

Concepts Covered: 

pedigrees, modes of inheritance, genetics diseases, OMIM database.

Prior Knowledge Required: 

genotypes, phenotypes, basic pedigrees, modes of inheritance (sex-linked, recessive, dominant, etc.)

Activity Notes

Days to Teach: 

Two 50 min class periods. Day one is for online disease research. Day two is to perform the wet lab.


Safety goggles, (6) 500ml beakers, iodine in dropper bottles (this will act as the mock Alkaptonuria test solution), volumetric pipette & tips (one set per lab station), six test tubes (per lab station), sugar, corn starch, food coloring, permanent markers, access to computers and internet (day one only). 

Teaching Tips / Activity Overview: 

  • Day ONE
    • Break the students into lab groups of 2-4.  These should be the groups that students will work in for the remainder of the lab.
    • Students should have access to computers and the internet.  The teacher should instruct students to go online and research the disease on the Online Mendelian Inheritance in Man (OMIM) website found at
    • By the end of the period, the students should produce a summary sheet to give to the Orina family.  This part of the activity can be done collaboratively as a group or individually depending on the teacher's preference.
  • Day TWO
    • Teacher should set up each lab station with a test tube rack, six test tubes, permanent marker, 10ml volumetric pipette, iodine dropper bottle (labeled Alkaptonuria test solution), and safety goggles. 
    • Students should report to their lab stations.  They should measure out samples the supply bench to measure out their urine samples and then return to their lab stations to test the samples and record the results on their lab sheet.
    • By the end of the day the group should have tested the six urine samples and used the results to construct a pedigree that displays the affected individuals within the Orina family.
  • Special Considerations and Lab Notes
    • The iodine will react with the starch in the fake urine samples and turn a dark brown, mimicking a positive test for Alkaptonuria.
    • The sugar in the negative test beakers is used to replicate the cloudy appearance of the cornstarch in the positive test beakers but should not react with the iodine.
    • Teachers may need to stir the solutions before each period so the starch doesn’t settle to the bottom of the beakers.
    • This activity gets the attention of kids with the “gross factor” of handling urine.  It may be necessary, however, to reassure students that it is fake urine and it is safe to handle.  (Technically speaking, all the ingredients of this urine are drinkable!)


Students will be assessed as they submit two different part of this lab. 

  • Students will first submit a one-page summary sheet about Alkaptonuria.  This sheet should be graded on the student's ability to use the OMIM database and compile the disease information into a comprehensive easy to understand fact sheet.  The disease summary sheet is worth 15 pts. 
  • The second part of the lab will be assessed using the post lab questions.


  1. Teachers can extend this activity by have students figure out the chance of inheritance for subsequent generations in the Orina family.
  2. Teachers can challenge students to create a pedigree for another family afflicted with a recessive disorder.


  1. "AKU Society." AKU Society. Web. 19 Apr. 2012. <>.
  2. "Alkaptonuria." Genetics Home Reference. 16 Apr. 2012. Web. 19 Apr. 2012. <>.
  3. "Alkaptonuria: MedlinePlus Medical Encyclopedia." U.S National Library of Medicine. U.S. National Library of Medicine. Web. 19 Apr. 2012.  <>.


Academic Standards
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