WHERE'D YOU GET THOSE GENES?

Master Teacher: Sharon Porter

Overview

Some of our coolest stupid human tricks, like rolling our tongues, making the Vulcan hand sign and being double-jointed, are a display of genes we inherited from our parents. Is it plain luck or is there more rhyme to the reason? In this lesson, students will manipulate Punnett squares to determine the patterns of dominant and recessive gene influence on first and second generations of humans and plants. Experiments in probability will affirm the data generated from the Punnett squares. We will even build custom beetles that are given recessive and dominant characteristics to bring method to our madness!

Learning Objectives

Students will be able to:

• Describe a dominant and recessive characteristic in a plant or animal.
• Define the concepts of an animal or plant being a hybrid or purebred.
• Use Punnett squares to predict patterns of heredity.
• Describe differences between first and succeeding generations of offspring.

Oregon Standards Available at:

http://www.ode.state.or.us/cifs

Science - Life Science

Understand structure, functions and interactions of living organisms and the environment.

Heredity

• Describe how the traits of an organism are passed from generation to generation.

Media Components

Video

Check the link at http://www.opb.org/edmedia/trs/ to find access to the video(s) from unitedstreaming™ referenced in this lesson plan.

• "Genes, Genetics and DNA" (24:13)
  o Clip: "An Introduction to Genes, Genetics and DNA" (00:48)
  o Clip: "Gregor Mendel's Rules of Heredity: Using Punnett Squares" (05:04)

• "Elements of Biology: Genetics: The Molecular Basis of Heredity" (20:00)
  o Clip: "Patterns of Inheritance" (02:31)
  

Web

• An Inventory of My Traits
  A PDF worksheet packet posted by the Genetic Science Learning Center at the Eccles Institute of Human Genetics, University of Utah for data gathering from simple classroom observations of human traits. This will be used for the Traits Tree activity to culminate the lesson.
  http://gslc.genetics.utah.edu/teachers/units/traits_inventory111.pdf
• Traits Tree Activity
  The Genetic Science Learning Center at the Eccles Institute of Human Genetics, University of Utah posted this lesson plan online which includes a blackline master for the leaves and large tree model for the Traits Tree activity.
  http://gslc.genetics.utah.edu/teachers/units/traits_tree.pdf
• Heredity Vocabulary Game
  Printed worksheet available by choosing the "Print" option on the page. The activity is also available online by matching the terms to their definitions.
  http://www.quia.com/mc/262311.html
• Portaportal - Internet Bookmark Organization
  Organize your bookmarks for this lesson using this free Internet service that allows for guest access.
  http://www.portaportal.com
• Kids Genetics
  GlaxoSmithKline presents an interactive site for students to understand the basic concepts of heredity. It is full of factual background material and two levels of games.
  http://genetics.gsk.com/kids/heredity01.htm
• Punnett Square
  This Web site, maintained by North Dakota State University, contains a list of activities. The resource used in this lesson is a PDF worksheet titled Punnett.Square.key.pdf. It is located about halfway down the list and is the companion handout to the WebLab Punnett Squares online activity.
  www.ndsu.nodak.edu/ndsu/drummond/activities
• WebLab - Punnett Squares
  Using roosters and lemmings, students test their understanding of the use of Punnett Squares in this online activity.
  http://www2.edc.org/weblabs/Punnett/punnettsquares.html
• Gregor Mendel Animation
  This Web site, powered by Macromedia Shockwave, is a delightful overview of Mendel's work with interactive examples of pea plant propagation.
  http://www2.edc.org/weblabs/Mendel/mendel.html
• The Gene School – Teacher Links
  Current genetic news is found at this Web site hosted by ThinkQuest.
  http://library.thinkquest.org/19037/teach_links.html

Materials

Per Student:

• Pencil
• Computer with Internet access: Java-enabled and Macromedia Shockwave installed
• PTC (phenylthiocarbamide) paper (available from Sargent Welch for $1.50 per vial of 100, Carolina Math and Science for $3.45 for 100 or Ward's Natural Science for $1.05 per vial of 100)
• Hard candy
• Handout: Heredity Vocabulary Game found at http://www.quia.com/mc/262311.html
• Handout: Leaf Cut-Out found at http://gslc.genetics.utah.edu/teachers/units/traits_tree.pdf
• Handout: An Inventory of My Traits found at http://gslc.genetics.utah.edu/teachers/units/traits_inventory111.pdf
• Handout: Punnett Squares found at http://www.ndsu.nodak.edu/ndsu/drummond/activities/Punnett.Square.key.pdf
  

Per Class and/or Group:

• Large bulletin board area for the Traits Tree
• Butcher paper for tree trunk
• Light green poster board or index paper for Traits Tree leaves
• Scissors and stapler
• Fine-line black markers (at least 15)
• Spreadsheet software on the teaching station computer

Prep for Teachers

When using media, provide students with a Focus for Media Interaction, a specific task to complete and/or information to identify during or after viewing of video, Web sites or other multimedia elements.

Session 1

• Order the PTC paper (phenylthiocarbamide) at least three weeks prior to the activities.
• Bookmark all Web sites and download video clips. Preview them for specific points you will use to teach students about the concepts of heredity and the vocabulary. Especially heed the cue for the video clip, "Gregor Mendel's Rules of Heredity: Using Punnett Squares," for pausing after the white rabbit square.
• Schedule the computer lab or mobile lab and allow one computer per student if possible. Check to see if the proper Windows Media Player is installed on the demonstration computer you will use for instruction. Make sure that this computer can be connected to a projector or a large-screen monitor for large-group instruction.
• Bookmark the Internet site at http://www.quia.com/mc/262311.html on every student computer for use for the vocabulary activity. You may use a favorite bookmarking strategy like Portaportal.com for organizing your students' navigations on the Internet.
• Prepare an oblong box (a shoe box works well) with a locker mirror pasted inside. Decorate the outside with "The World's Most Unique Genetic Experiment!" in elaborate lettering.
• Use spreadsheet software to create a table with percentage formulas so that you can quickly and easily display student traits and percentages (a sample is located at the end of this lesson plan).
• Duplicate for each student:
  o "An Inventory of My Traits" found at http://gslc.genetics.utah.edu/teachers/units/traits_inventory111.pdf
  o "Heredity Vocabulary Game" found at http://www.quia.com/mc/262311.html
  

Session 2

• Using the blackline master found at http://gslc.genetics.utah.edu/teachers/units/traits_tree.pdf, reproduce enough Traits Tree leaves so that each student has one leaf.
• Duplicate the Punnett Square handout found on the Internet at http://www.ndsu.nodak.edu/ndsu/drummond/activities. Be sure to remove the answers before reproducing this page.
• Organize the materials for the culminating activity: PTC paper, hard candies for each student, stapler (or tape) and scissors.
• Prepare the large tree trunk out of butcher paper and have it on a bulletin board or some surface that is within reach of the students.

Introductory Activity

Step 1: Hold up a long, oblong box with "The World's Most Unique Genetic Experiment!" printed on the outside. Invite a student to come up and open the box so that the class cannot see in but the student up front can see their reflection. Ask the student what was viewed in the box. When the student answers "Me!", ask the class why the box was labeled so. (Various answers but look for "We are all different because of our parents," etc.) Lead the answering by saying, "I wonder what characteristics are given to us by our parents." "I don't look exactly like my folks." "How does this work?"

Step 2: Pass out copies of An Inventory of My Traits handout found at http://gslc.genetics.utah.edu/teachers/units/traits_inventory111.pdf

Step 3: Play the video clip, "An Introduction to Genes, Genetics and DNA" (00:48), from the video, "Genes, Genetics and DNA" (24:13). As a Focus for Media Interaction, have the students draw a star by the traits they possess shown in the video clip on their copy of An Inventory of My Traits handout.

Step 4: When the video clip finishes, ask the students to determine the traits they possess shown in the video first by marking their answers. Ask for a show of hands as to the numbers of students who can roll their tongues and who have hitchhiker's thumbs. Note those in the spreadsheet you created as part of teacher prep for this lesson to calculate the percentages. Project on the screen from your computer for the class to see. Have the students finish the page. By a show of hands, count the number of students who possess each characteristic and enter the numbers into the spreadsheet.

Step 5: Ask the students to consider the data. Questions to ask are: "How do we know what genes are passed on?" "Are these numbers we see from our classroom typical?" "Would more surveys change the numbers?" "Can we predict how many children will have allergies if we know the parents have allergies?" "Is there a more organized way to find out the answers to these questions?"

Learning Activities

Session 1 (continued)

Step 1: To provide information about genetics, play the video clip, "Patterns of Inheritance" (02:31), from the video, "Elements of Biology: Genetics: The Molecular Basis of Heredity" (20:00). As a Focus for Media Interaction, the students will write down definitions as they encounter them in the video clip onto the Heredity Vocabulary Game handout. If necessary, repeat the clip.

Step 2: Review with the students the definitions they wrote while viewing the video clip. Say to the students, "Some definitions we need are missing. Let's find some other answers we will need by going to the Internet at this address: http://www.quia.com/mc/262311.html. We will play the matching game to discover more vocabulary words. When you have a match, write that definition on your vocabulary sheet."

Step 3: Tell the students "We STILL do not have all the information we need to answer why we are the unique people we are." "Just how do we predict what kind of trait is passed on from one generation to the next? Is tongue rolling dominant over non-tongue rolling? Blue eyes over brown? Let's look at the tools we use to help us predict the outcome of traits through the generations." View the video clip, "Gregor Mendel's Rules of Heredity: Using Punnett Squares" (05:04), from the video, "Genes, Genetics and DNA" (24:13). As a Focus for Media Interaction, inform students that they will be using the information they learn about Punnett squares to create their own in a few moments. They should pay particular attention to how they are built and how to read them.

Step 4: Pause the video clip after the Punnett square demonstration of the hybrid rabbits' square (when the student answers, "white rabbit" and the speaker in the film says, "good!"). Direct your students to complete their own Punnett squares found on the bottom of the vocabulary page we have been using. This square involves tall and short plants.

Step 5: Review their answers before going back to finish the video clip.

Step 6: As a Focus for Media Interaction, tell students, "Now, we will get more practice in using Punnett squares to help us predict the traits passed down to the next generation." Direct students to log on to http://genetics.gsk.com/kids/heredity01.htm and click on the button found halfway down the page that says alternately "level 1/Heredity learning activity/level 2/click here to play." When they enter the screen, direct the students to press "just the facts, please" as a review of the concepts used in the game.

Step 7: To play the game, direct students' attention to the left side of the screen where the two-step directions are found. Note: The game will not continue until the "Close" button is pressed every time an action is evaluated. The pop-up boxes from Mr. U. Gene contain vocabulary reinforcement. Have the students click and drag the combinations into the Punnett square to get the correct combinations of alleles.

Step 8: Proceed to the right side of the screen to the Pedigree Chart to determine the percentage of dominant and recessive alleles present in the parents on the left. Drag the percentages to the correct squares. Ask the students if they note any significance to the use of squares and circles in the pedigree chart. "What is the significance of the lines connecting the boxes and circles?" Check their answers by clicking on the button labeled "How to Read Pedigree Charts."

Session 2

Step 1: Direct the students to return to the Internet site found at http://genetics.gsk.com/kids/heredity01.htm. As a Focus for Media Interaction, tell students that they will complete another Punnett square to reaffirm their learning from the previous session. This time we will click on the button to enter the games but will proceed to the "next level" at the screen we encountered yesterday. Our new screen will read "Punnetts and Pedigrees." Again, it is important to read the directions on the left side of the screen. Complete the Punnett square on the left side. Note: There is a distracter here in the orange beetle. Just like the grey rabbit mentioned in the video clip viewed in an earlier part of the lesson, these traits are not blended so no beetles are orange.

Step 2: Proceed to the right side of the activity to complete "The Pedigree Chart." At the end of the activity, direct the students to exit the game. Note: The beetles with curly hair are female. The answers have to be correct to move to the exit part of the game.

Step 3: As a Focus for Media Interaction, tell students that they will go to another Web site to test for understanding. Direct students to complete the screens found at http://www2.edc.org/weblabs/Punnett/punnettsquares.html. These screens are interactive and will serve as a review of the concepts we have studied in the last session. The Punnett Squares handout is used to collect answers for this activity. When students hand in the activity and time permits, have them visit an animation of Gregor Mendel found at http://www2.edc.org/weblabs/Mendel/mendel.html.

Culminating Activity

Step 1: Give each student a leaf cut-out you reproduced from the Internet site http://www.ndsu.nodak.edu/ndsu/drummond/activities/Punnett.Square.key.pdf.

Step 2: Direct the students to mark their responses for the traits "earlobe attachment" and "tongue rolling" on the form.

Step 3: Give the students the PTC paper and have them place it on the tips of their tongues. The hard candy is to erase the bitter taste. Note: This is a harmless, bitter-tasting chemical that is controlled by a single gene. The PTC-tasting gene is dominant and may explain some young children's revulsion to bitter-tasting vegetables and serve as a possible link between the ability to taste PTC and smoking behaviors. It is present in 70% of the population. Have the students mark "yes" or "no" to this trait on their leaf forms.

Step 4: Direct the students to place their leaves on the Traits Tree, forming a visual representation of the traits found in the classroom. There are multiple traits on the form so accuracy to the correct branch of the tree is imperative.

Step 5: If time permits, calculate the percentages of people who can roll their tongues, have attached earlobes and can taste PTC paper. (The formula would be number of leaves on that branch divided by the number of leaves times 100 to equal the percentage.)

Cross-Curricular Extensions

Math

• Calculate the percentages of other human traits found in the classroom (examples: blue eyes or hair color).
• Survey another class to see if a larger sample affects the percentage of traits.
  

History and Social Studies

• How has genetic engineering entered into everyday life? See the Internet site http://library.thinkquest.org/19037/teach_links.html for links to genetic news for a current event newspaper called "Heredity Herald."
• Research events in history that have a gender-, race- or ethnic-based catalyst.

English and Language Arts

• Debate issues can be organized around current events focusing on genetics. Genetically engineered food, cloning and genetic counseling are all topics in the news.
• Scenarios can be used as writing prompts. Some excellent ones are found in the Teacher's Guide for the video, "Genetics: The Molecular Basis of Heredity." (Check the link at http://www.opb.org/edmedia/trs/ to find access to the blackline master(s) from unitedstreaming™ referenced in this lesson plan.) For example, you go to a store (in the not-too-distant future) and want a candy bar but the bracelet on your arm that the computer reads at the checkout stand disallows the purchase. It seems you exceed the allowable kilograms for your age and height. What other information might be stored in the computer and for what purpose? What other ways can this computer information affect the rest of your day?

Community Connections

• Guest speakers can be invited to speak to the students about the use of genetics in their field of occupation. For example, veterinarians could talk about dog breeds, a cattle rancher could talk about breeding herds, and a hair technician could talk about inherited characteristics such as baldness, texture and color.

Sample Spreadsheet