Pedigrees and the Inheritance of Lactose Intolerance

Contributor
Howard Hughes Medical Institute-Biointeractive
Type Category
Instructional Materials
Types
Lesson/Lesson Plan
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Description

In this activity students analyze a family’s pedigrees to make a claim based on evidence about mode of inheritance of a lactose intolerance trait, determine the most likely inheritance pattern of a trait, and analyze variations in DNA to make a claim about which variants are associated with specific traits. This activity serves as a supplement to the film Got Lactose? The Co-evolution of Genes and Culture (http://www.hhmi.org/biointeractive/making-fittest-got-lactase-co-evolution-genes-and-culture). The film shows a scientist as he tracks down the genetic changes associated with the ability to digest lactose as adults. A detailed teacher’s guide that includes curriculum connections, teaching tips, time requirements, answer key and a student guide can be downloaded at http://www.hhmi.org/biointeractive/pedigrees-and-inheritance-lactose-intolerance. Six supporting resource and two “click and learn” activities are also found on the link.

Intended Audience

Educator and learner
Educational Level
  • Grade 12
  • Grade 11
  • Grade 10
  • Grade 9
Language
English
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

HS-LS3-1 Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

Clarification Statement: none

Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
This resource can be used as supplemental activities after teaching a genetics unit. Students will need prior knowledge on the central dogma (flow of genetic information among gene, proteins, and traits), complementary base-pairing rules, basic genetic terminology, inheritance patterns, and mutations. The student resource includes a good explanation of pedigree symbols but teachers need to provide additional instruction on pedigree analysis. The teacher’s guide suggests showing the film “Got Lactase? The Co-evolution of Genes and Culture “before teaching the lesson. Prior to showing the film, teachers can engage students by asking if they know someone who is lactose intolerant and asking them to make a claim about the mode of inheritance of the lactose intolerant trait. Teachers can use the accompanying film guide (http://www.hhmi.org/biointeractive/film-guides-got-lactase-co-evolution-genes-and-culture) that requires students to focus more on the content of film. After the film, teachers can lead students in a whole-class discussion on their claims about the mode of inheritance. To collect additional evidence to support their claims, students will analyze three family pedigrees and complete the questions on the student handout. At this point, teachers can lead another whole-class discussion about new data and evidence to support their claims. Part 2 of the student pages, asks students to analyze variations in DNA sequences and make a claim about which mutations are associated with specific traits. After completing Parts 1 and 2, teachers can assign students to groups to create a whiteboard argument presentation. Teachers can use the whiteboard presentation to evaluate students’ understanding of the content. If additional teaching is required, teachers can use one of the supporting materials or the “click-and-learn” resources.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
This resource addresses the practice by asking students to analyze pedigrees and use the evidence to make a claim about the mode of inheritance for the lactose intolerant trait. Also, students analyze variation in DNA sequences and use the evidence to make a claim about which variants are associated with specific traits. Teachers need to provide instruction on how to analyze pedigrees to determine the mode of inheritance before using this resource. If students are unfamiliar with developing claim and evidence responses, teachers need to model the process.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
This resource does not address how the information in DNA is used to direct protein synthesis and influence an organism’s characteristics. If students do not have a conceptual understanding of this content, they will only analyze the pedigrees to get the correct answers. Understanding this content will help students develop stronger claim-evidence responses.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students analyze pedigrees to understand the patterns of inheritance of the lactose intolerance trait. The pedigrees by themselves indicate a correlation but don’t support students’ understanding of the mechanism for passing of the trait. Students perform genetic analysis of the pedigrees to determine the mode of inheritance (dominant/recessive and autosomal/sex-linked). This analysis helps students develop a conceptual understanding of how the lactose intolerance trait is transmitted from parent to offspring. After completing the first pedigree and developing a claim, teachers need to skillfully guide students in a making a connection between how the trait is inherited and the expression of its phenotype. Students analyze three additional pedigrees to collect data to support their claim. Students use knowledge gained from pedigrees to analyze DNA sequences and identify changes in DNA that are associated with lactose tolerance and support their claim by providing at least three pieces of evidence. Teachers need to make sure students understand mutations and discuss the correlation between mutations and variations in a population.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This resource is strongly aligned to NGSS. It asks students to analyze and interpret pedigrees, make claims about mode of inheritance and variants, and use evidence to answer questions and support their claims.

  • Instructional Supports: Students use the claim-evidence-reasoning model to study a pedigree to make a claim based on evidence about the mode of inheritance. Students use critical thinking and reasoning skills to determine the most likely inheritance pattern of a trait tracked in a pedigree and the genotype of individuals included in the pedigree. This resource provides students with an authentic opportunity to study a common trait (lactose intolerance) in the human population. Students needing additional support can use the “click and learn” resources. This resource should be used after teaching a genetics unit. The teacher’s guide is very teacher-friendly and includes a tremendous amount of support materials. It provides a brief overview, key concepts and student learning objectives, curriculum connections, time requirements, prior knowledge, teaching tips, background information, answer key, and student handout. The student handout includes claim and evidence questions but there is not an option to share their argument. Teachers can incorporate the whiteboard argumentation into a whole-class discussion or gallery walk.

  • Monitoring Student Progress: This resource includes a quiz for the film. The student handout contains questions that require students to think critically. In the handout students are asked to make a claim after completing each activity. If white board protocol is used, students should be provided with rubric for their presentations.

  • Quality of Technological Interactivity: This resource provides opportunities for students to view online videos and learn more content about lactose intolerance through “click and learn” activities. However, it does not provide opportunities for interactive student engagement.