It's in Your Genes: Finding a Gene on a Chromosome Map
Lesson 14 of 19
Objective: SWBAT use a pedigree and jigsaw puzzles to explore how scientists use genetic information from a family to identify a gene associated with a genetic disorder.
To engage students in the lesson I show a video of a woman who has neurofibromatosis. The reason I show this video is that neurofibromatosis is a genetic disorder, which is what students will explore during this lesson.
Once the video ends, I share the following facts about neurofibromatosis:
- One of the most common autosomal dominant disorders, affecting approximately 1 in 3,000 individuals.
- Gene responsible for NF1 is NF1
- Gene is located in chromosome 17
- Genetic Disorder NF1 runs in families and exhibits an autosomal dominant patten of inheritance
- Contains dominant pattern of inheritance
Students complete a Finding a Gene on the Chromosome Map activity, courtesy of Genetic Science Learning Center.
In this activity students use a pedigree and jigsaw puzzles to explore how scientists use genetic information from a family to identify a gene associated with a genetic disorder. (SP2 - Developing and Using Models)
Prior Knowledge Needed
DNA, chromosome, gene, protein, patterns of inheritance (dominant vs. recessive, autosomal vs. sex-linked)
Copies of student handouts ( Finding a Gene on the Chromosome Map)
- Students will learn that all humans have the same genes, arranged in the same order along the twenty-three pairs of chromosomes
- Students will understand every person is unique because the information carried in genes differs slightly from person to person, i.e. an individual inherits one form (or allele) of every gene from each of his or her parents, resulting in a unique combination. (MS-LS3-2. Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.)
- Students will be able to explain how a mutation (or permanent damage in the DNA sequence) may cause a gene to be defective, possibly causing a medical condition known as a genetic disorder.(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/CCC - Cause and Effect)
- Students will gain experience using a pedigree to determine the inheritance pattern of a genetic disorder.
- Students will understand that scientists use a pedigrees as a tool to identify a gene associated with a particular genetic disorder.
Teacher Note: Prior to this lesson complete 15 class sets (class of 30) of 12 genetic puzzles. I cut puzzles individually with numbers attached so students can grab the puzzles and place them on top of the pedigree chart. From prior experience, I know students are more engaged when they are able to physically manipulate learning tools.
- As a class, read student page S-1 "Finding a Gene on the Chromosome Map". The following are key areas to emphasize: puzzle piece/gene analogy, family jigsaw puzzle (child gene is a combination of mom and dad genes), and relationship between genetic disorders and gene mutations.
- Model how to use a pedigree by modeling one found on student page S-2.
- Explain to students that in this activity they will pedigree analysis to find inheritance patter of a genetic disorder. Explain to students that geneticists use this same approach during genetic counseling.
- Give each pair of students envelope with genetic puzzles.
Advice: Depending on the level of your class, you might need to point out that Person 1 is the first person to have the disease in the pedigree chart and, as a result the mutated gene is a red puzzle piece. This gives students a starting point that they are looking for a red puzzle piece. This makes the task less daunting and decreases frustration that may arise for some students.
In this section of the lesson, students visit cK-12 to read a text on Human Chromosomes and Genes.
Topics Covered in Text
Once students complete reading, students answer the following questions:
- Describe human chromosomes.
- Compare and contrast human autosomes and sex chromosomes.
- What is SRY?
- Why are females the "default sex" of the human species?
I reinforce the reading by showing the Gene vs. DNA vs. Chromosomes video.
I have included a Genome Poster in the resources. It visually identifies genes,genetic traits, and disorders on their corresponding chromosomes.
In this section of the lesson students elaborate on what they have learned by completing a close reading of Neurofibromatosis Type 1.
Students use Writing in the Margins as a strategy to make text accessible.
Writing in the margins engages readers in the reading task and allows them to document their thinking while reading. Both writing in the margins and drawing in the margins engages students in actively thinking about the texts they read. The power of this strategy is not the actual act of writing and drawing in the margins; instead, it is the thinking processes that students must undergo in order to produce such ideas.
For this particular text students use the Summarize strategy. (RST.6-8.1 Cite specific textual evidence to support analysis of science and technical texts)
Briefly summarize paragraphs or sections of a text. Summarizing is a good way to keep track of essential information while condensing lengthier passages.
state what the paragraph is about
describe what the author is doing
account for key terms and/or ideas.
In this section students complete an Exit Slip where they are required to write an evidence based argument to explain the genetic component of neurofibromatosis. (SP7 - Engaging in Argument from Evidence/W.7.1 - Write arguments to support claims with clear reasons and relevant evidence.)