Reading Apprenticeship Inspired Assignment or Lesson
Reading Apprenticeship Inspired Assignment or Lesson
The purpose of this activity is to give students an opportunity to analyze human genetic data presented in a pedigree chart. Initially inheritance data is presented to students in analysis of the results of controlled crosses. For analysis of human genetics, controlled crosses are not possible. Instead, scientists use pedigree analysis to study human genetics.
This activity has the following objectives.
- Students will gain experience in reading a pedigree chart
- Students will deduce genotypic data from historical data presented in a pedigree chart
- Students will experience a real-life application of genetic data when acting as a genetic counselor
- Students will interact with classmates as a community building exercise
The students will work from prepared pedigree charts. Organization of a pedigree chart is discussed prior to beginning the activity. Students also have experience in deducing parental genotypes from the phenotypes of offspring from genetics problems. I created charts that represent different modes of inheritance.
The students will work as a group and at the end of the activity, each member of the group will prepare a short report based on the prompts provided. The report includes a prediction of inheritance for prospective parents. Each student will also guess at the disorder, based on the mode of inheritance from genetic disorders discussed in the text. If time allows a group member may present their report. I evaluate reports based on the analysis of the chart that led to that determination. My goal is to provide practice in reading pedigree charts and not for the students to hand in a perfect analysis of the data.
The students are prompted to draw on concepts learned earlier in the semester to analyze this human genetic data. The introduction to the activity (see details) provides scaffolding to help students retrieve their understanding of inheritance. Active learning exercises have been shown to help make content relevant and to help students think about their own learning and including the role of a genetic counselor connects this activity to real-life experience.
I begin by asking students what they think genetic counselors do and how they predict the possibility of a child inheriting a particular trait. Following a short discussion, a pedigree chart is projected, and students are asked to make sense of the chart, working individually or in pairs, using prompts (What do you notice? Is anything confusing to you? Do you have questions about anything you see?). After the discussion, students work in groups of 4 to analyze one or more pedigree charts. One student acts as a facilitator, taking notes and keeping the activity on tract. For help with analysis, students receive the following prompts:
- What do you notice about the inheritance of the trait at first glance?
- Fill in the genotypes of the individuals in the chart based on the phenotypes of the parents and offspring. Remember that you may not be able to determine all genotypes initially.
- Construct a Punnett square that illustrates the probability of your client’s child inheriting this trait. It may not be possible to give a precise answer (why is that?)
It is possible to provide charts in which the mode of transmission is unknown with more advanced classes. You may identify the trait or ask the students to guess from the genetic diseases studied in class.
At the end of the exercise, each student turns in their report. I end with a video from TedEd in which a genetic counselor explains her position. I plan for the activity to require the class period (75 minutes), but it can be tailored to the requirements of the instructor.
Students will work from provided pedigree charts. Links to my charts are provided below. A link to a TedX talk by a real genetic counselor and additional links to information about genetic counseling are also provided.
TEDX video by a genetic counselor
National Society of Genetic Counselors
American Board of Genetic Counseling
