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Activity: why do some mutations cause genetic disorders?

Make science come alive in your classroom with this free hands-on investigative activity aligned to middle school NGSS standards.

Activity: why do some gene mutations cause genetic disorders?

Imagine learning that you have a gene mutation that could result in a serious disease. Now imagine finding out that if you catch it early enough, you can take steps to lessen the effects of the disease.
In fact, there are many genetic disorders (diseases caused by gene mutations), for which early detection can help improve lives. In this activity, students explore one of these disorders: galactosemia. Students will use real genetic data to understand why some mutations cause galactosemia and others don’t. They will also take on the role of a doctor, interpreting test results of patients with galactosemia and learning how newborn screening programs can detect mutations early.
A healthcare worker holds an infant’s foot, which has been pricked at the heel. The healthcare worker dabs blood from the heel onto a piece of paper.
An infant being screened for genetic disorders. Image credit: “Phenylketonuria testing" by U.S. Air Force photo/Staff Sgt Eric T. Sheler, Public Domain.

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This activity is designed to be completed in two 45-minute class periods, with additional time required for follow-up creative projects. The activity consists of the following parts:
  • Setting the stage—Students read and demonstrate understanding that mutations in a gene can cause changes to the structure and function of the protein, which can have effects on the organism. (10 minutes)
  • Investigation (Part 1)—Students translate codons and identify chemical properties of amino acids. Students construct an explanation for why certain mutations result in galactosemia, and others don’t. (20 minutes)
  • Investigation (Part 2)—Students read about newborn screening programs, and look at test results to identify a patient with galactosemia. (10 minutes)
  • Let's get creative!—Students imagine they are public health officials. They research which genetic conditions are included in their state's newborn screening program, and create an educational poster. (45 minutes)
  • Keep creating!—Students can choose from additional project ideas. Each project encourages students to combine scientific knowledge with creativity to produce something new.

NGSS performance expectations

MS-LS3-1. Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

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