Goal: to Trace the Gene That Causes a Genetic Disorder Through A

Goal: to Trace the Gene That Causes a Genetic Disorder Through A

Activity: Investigating a Human Pedigree

Goal: To trace the gene that causes a genetic disorder through a

fictional family.

Problem: As a scientist, you’ve noticed that a genetic condition, “Whirling Disorder,” runs in families, and you want to find the gene responsible for it. (Individuals afflicted with this disorder let loose and dance uncontrollably when they hear Rolling Stones tunes, even if remade as Musak!)

Your first step is to identify a large family in which some individuals have the disorder, and others don’t. After enlisting the family’s support and collecting DNA samples from all family members, you’re ready to begin looking for the gene. Next, you draw up a pedigree, which is a diagram that shows how family members are related and which individuals have “Whirling Disorder.”

Background Information: Here’s one way to think about genes. Say the genetic information in each family member is like a jigsaw puzzle. Each puzzle piece would represent a set of genes organized in a specific way, similar to a chromosome. (Instead of 23 sets of chromosomes in every cell – each with thousands of genes, think of jigsaw puzzles of genes in every cell.) Because all humans have the same set of genes, arranged in the same order, every family member would have the same basic set of puzzle pieces. A genetic human jigsaw puzzle might look like this:

But the information carried in genes differs slightly from person to person. This is what makes each of us unique. As a result, the colors of the puzzle pieces would be different between family members. While some relatives might share puzzle pieces of a certain color, other pieces would be different. Only identical twins share the exact same combination of colors.

Materials: “Whirling Disorder” family pedigree chart, genetic jigsaw puzzle sheet with 12 members of the family represented and a blank “worksheet” puzzle.

Procedure:

  1. What I Know: Write two sentences about what you already know about pedigree charts and human inheritance.
  1. Study the family pedigree chart and then study each puzzle. Each puzzle has a number that corresponds to an individual in the pedigree.
  2. Find the puzzle piece that is responsible for “Whirling Disorder.
  3. What I Observed: Write the number of the puzzle piece that is responsible for “Whirling Disorder.”

Number of Piece ______

  1. Questions: Answer the following questions in complete sentences.
  2. How did you determine which puzzle piece is responsible for “Whirling Disorder?”
  1. How do you know the puzzle piece you chose is the right one?
  1. In this simulation activity what unit of heredity does each puzzle piece represent?
  1. Is “Whirling Disorder” sex-linked? Explain your answer.
  1. Is “Whirling Disorder” dominant or recessive? Explain your choice.
  1. What I Wonder: Pose a question that you may still have concerning the topic of this activity.
  1. Claim and Evidence Writing Prompts: Use the following prompts to help you construct your lab conclusion, What I Learned.
  • Goal: State the goal of this lesson.

The goal of this lesson is…

  • Claim: What did you learn from the activity that satisfies the goal of this lesson? This is an I Learned statement.

I learned that…

  • Evidence: How can you prove from your observations that you learned what you claim? This can be a general statement that you will explain in detail in your explanation.

I know this because….

  • Explanation: Use specific data from your observations to support your claim and describe the evidence. Use details to support your claim.
  • Concluding Statement: Reword the goal and either add information you learned about the topic from your text book, class discussions, and/ or personal research OR you can extend the statement by adding a relevant question.
  1. What I Learned: Write at least a one paragraph summary of what you learned from completing this activity. Use the Claims and Evidence Writing Prompts to help you compose your summary.
  1. What I Wonder: Pose a question that you may still have concerning the topic of this activity.
  1. Questions: Answer the following questions in complete sentences.
  2. How did you determine which puzzle piece is responsible for “Whirling Disorder?”
  1. How do you know the puzzle piece you chose is the right one?
  1. In this simulation activity what unit of heredity does each puzzle piece represent?
  1. Is “Whirling Disorder” sex-linked? Explain your answer.
  1. Is “Whirling Disorder” dominant or recessive? Explain your choice.
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