Creating Karyotypes

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Objective

SWBAT analyze human chromosomes to determine genetic traits that will be expressed by that individual based on the genetic composition of the sample karyotype.

Big Idea

Calling all DNA detectives! Students will examine sample karyotypes to identify gender and common genetic abnormalities.

Hook - Visualizing Chromosomes

5 minutes

Students will be challenged to examine the sample chromosomes from the Human Chromosome handout by identifying the location of specific genes on each chromosome.  Students will answer the accompanying comprehension questions to further understanding of the structure of chromosomes.

After students have had the opportunity to complete the handout, the class will review the correct responses.  Students are encouraged to ask for clarifying details regarding the anticipatory activity.

The video clip documents the whole-class review of this activity:

Direct Instruction - Connecting DNA and Chromosomes With Karyotypes

15 minutes

Students will asked to activate their prior knowledge regarding DNA and chromosomes from a previous lesson as the class moves forward in their introduction of karyotypes.  Students will record the Karyotypes Lecture Notes on their paper to support their understanding of the following concepts:

  • The relationship between DNA, genes, and chromosomes
  • The process to create a karyotype using homologous chromosomes
  • The genetic information that can be gained from analyzing a karyotype

 

DNA and Chromosomes

 

Students are encouraged to ask questions for clarification or additional details throughout the lecture to support student learning.  

Students will use these lecture notes as a reference in the next activity in the next section where they will be tasked to create their own paper karyotype.

 

Guided Practice - Creating Karyotypes

25 minutes

Students are encouraged to keep their lecture notes and textbooks out to use as a reference for this hands-on activity to reinforce the concepts of using karyotypes to understand how DNA will determine the traits expressed by an individual.

In preparation of this activity, each student will need the following supplies:

  • Student Handout- Creating a Karyotype that contains the directions and sample karyotype image
  • 4 Karyotype Samples - Students will be cutting this up during the activity so it is important not to print back-to-back.  Students will only get one of the four sample karyotypes.
  • Scissors
  • Glue stick (recommended) or tape
  • A separate sheet of paper (copy paper or lined paper) to create the karyotype on

Once the students have received the necessary supplies, it is time for our DNA Detectives to emerge.  

Step #1: Students are tasked with the responsibility of pairing homologous chromosomes for each of the 1-22 pairs, as well as identifying the sex chromosomes to make the 23rd pair.  Students will use the sample karyotype as a guide in identifying the number identification of each chromosome, as well as identifying its homologous pair.  Students will need to use the scissors to cut out each individual chromosome from the sheet and affix it next to its homologous pair on their sheet of paper.  Students will complete this process until all 22 autosomal chromosomes have been paired up, as well as the 23rd set of chromosomes to determine gender.  HINT: Students should use the height of the chromosomes and the banding pattern to identify the homologous pairs.

Step #2: Once students have completed their karyotype it is time to analyze the chromosomes to determine the gender and whether there are chromosomal abnormalities.  

Step #3: Students will use their newly created karyotypes as a reference to respond to each of the comprehension questions at the bottom of the student activity handout.

Sample of Student Work #1:Paper Karyotype: This sample demonstrates a karyotype for a genetically normal female.

Sample of Student Work #2:Paper Karyotype: This sample demonstrates a karyotype for a female with trisomy 21 also known as Down Syndrome.

Sample of Student Work #3:Paper Karyotype 3: This sample demonstrates a karyotype for a male with Klinefelter's Syndrome.

Close - Virtual Karyotypes

10 minutes

Students will work in collaborative pairs to debrief their responses to the activity comprehension questions.  Keep in mind that student-pairs will have different responses based on which one of the possible karyotypes they received at the start of the activity.

The students will share in a whole-group discussion to identify the correct identifications of the four sample karyotypes:

#1:Gentically Normal Male

#2: Down Syndrome Female

#3:Genetically Normal Female

#4: Klinefelter's Male

For homework, students will complete an online karyotype activity as homework.  Students will record their observations and answers to the questions that are contained within the site.  The website was created by University of Arizona's Biology Project and provides the opportunities to create and analyse chromosomes while creating a karyotype.

Student Work - OL Karyotype Activity - The University of Arizona's Biology Project provides an amazing activity for students to work with real data to reinforce the content of today's lesson.  This sample of student work demonstrates the opportunity to practice our genetics curriculum while infusing technology and real life examples into the experience!