PUTTING DNA to WORK: High School Virtual Field Trip

Transcription

1 PUTTING DNA to WORK: High School Virtual Field Trip Overview In this activity teams of students will gather detailed information from the online exhibit Putting DNA to Work. Students will explore the question: How can the knowledge of DNA sequencing be applied in the future? Directions 1. Instruct students to explore the Introduction and DNA Sequence sections of the exhibit. They may work individually or in groups and may visit the sections in any order. 2. Students should then be assigned to one of three expert groups and explore the rest of the exhibit using their assigned focus. Forensics: How are sequences used to detect inherited diseases and identify suspects? Plant Domestication: How is information about plant DNA used to change and improve agricultural crops? Public Health: What types of new technology are being used to identify unknown disease causing agents? 3. Once students have explored the entire exhibit they should remain in their expert groups to answer the questions. 4. Lead a whole class discussion, allowing each group to report out the information they have gathered and to discuss answers. Introduction 1. Find the percentage of genes that each of the 5 organisms shares with humans. Organism Mouse Fruit Fly Chimpanzee Yeast Plant Percentage 1

2 2. If people share 100% of the same genes, why are we all not identical to each other? 3. Circle the larger item in each pair: Cells Tissues Genes Chromosomes 4. What is meant by the term genome? 5. About how many genes are found in the human genome? 6. You inherit one copy of your genome from each parent. a. How many copies of every gene sequence do you inherit from your parents? b. How many chromosomes do you inherit from each parent? DNA Sequence 1. Describe the shape of a DNA molecule: 2. What are the building blocks of DNA called? 2

3 3. How many kinds of building blocks are there? 4. How can one of the strands of a DNA molecule be used like a photographic negative? 5. When the building blocks pair up, which ones pair together? 6. Probe the DNA sequence using 3 and 6 letter probes and record the number of matches. Probe (3 or 6 letters) No. Matches Found on Screen No. Matches Found in the 3 Billion Letter Human Genome No. Matches Expected in 3 Billion Random Letters CAT 7 52,612,857 44,767, How does the length of the DNA probe affect the number of matches the probe will find in the human genome? 8. If every cell in the body contains all of the same DNA sequence, then why are some cells so different from others? Forensics Expert Group Your team of experts will gather in-depth information on how sequences are used to detect inherited genetic diseases and to identify a suspect. The information you gather on these topics will be vital for the group discussion, which will focus on the question: 3

4 How can the knowledge of DNA sequencing be applied in the future? Explore the Inherited Diseases and DNA & Criminal Justice sections and use the following guiding questions: 1. What is a mutation? 2. For each mutation identify the changes in the message: TMET OD REAM EMIT TO DREAM TIIM ET ODREAM TAME TO DREAM Single letter change Insertion Deletion Reverse 3. Why do you need to look at two copies of a gene to tell if a person has inherited a disease? 4. What is meant by the term carrier? 5. How many letters are involved in the genetic defect that causes sickle cell anemia? 6. Hemochromatosis is an inherited genetic disease. a. What happens to a person with hemochromatosis? 4

5 b. What procedure do doctors use to treat hemochromatosis? 7. How could the falsely imprisoned benefit from DNA sequencing technology that might not have been available at the time of their original trial? 8. How many sites in the DNA sequence are used by the FBI s Combined DNA Index System (CODIS)? 9. What are the chances of a suspect perfectly matching a sample at all CODIS sites? 10. Use the interactive to compare DNA samples from 3 suspects to a DNA sample left behind at the scene of a crime. a. Which suspect matches the sample? b. Which suspect is probably a sibling? c. Which suspect is most likely unrelated to the other two? Plant Domestication Expert Group Your team of experts will gather in-depth information on the use of DNA sequencing information from plants to change and improve agricultural crops. The information you gather on this topic will be vital for the group discussion, which will focus on the question: How can the knowledge of DNA sequencing be applied in the future? Explore the Improving Crops section and use the following guiding questions: 5

6 1. Agricultural crop plants look very different from the original wild plant ancestors of years ago. What techniques did our human ancestors use to help create these changes? 2. List three differences between the following characteristics of ancient teosinte and modern corn (maize). a. Ears: b. Kernels: c. Number of branches: 3. How is a genetically modified organism (GMO) created? Using the Maize Mutants interactive, your group should complete the following chart by finding 2 genes that control each of the following characteristics of the corn plant: 4. Kernel color: Chromosome # Name of gene What does this gene do to the plant? 5. Leaf texture or color: Chromosome # Name of gene What does this gene do to the plant? 6

7 6. Silk/Tassels: Chromosome # Name of gene What does this gene do to the plant? 7. What does the "transgenic" gene on chromosome 7 increase resistance to in Bt crops? 8. Compare the amount of modern corn produced per acre in 2002 with the amount that would be produced by teosinte if it was used as a crop plant today. Corn Yield (tons per acre) Teosinte 9. If we were still planting teosinte as a food crop, how much more land (in millions of acres) would be needed to get the same yield as modern corn (2002 figures)? Public Health Expert Group Your team of experts will gather in-depth information on new technology using DNA sequences to quickly identify unknown disease causing agents. The information you gather on this topic will be vital for the group discussion, which will focus on the question: How can the knowledge of DNA sequencing be applied in the future? Explore the Infectious Disease section and use the following guiding questions: 1. What does SARS stand for? 7

8 2. Using the Identify the Disease activity try to quickly identify what virus the sequence belongs to. What is the name of the virus that matches the unknown DNA sequence? Human virus 3 3. What new DNA technology was used as an identification tool to find the cause of SARS? 4. Answer the following questions about creating a virus chip: a. When creating a virus chip, how many viral DNA sequences (or dots) are contained on the grid? b. How many base pairs, or letters, are contained in each DNA sequence? c. How many different virus strains are represented on the chip? d. The virus chip produces different colored dots. What color dots indicate sequences that match the unknown virus? e. What determines the brightness of each bar on the bar code? 6. Which was faster and easier to use in finding a match for the human parainfluenza virus 3, the method using DNA letter sequences or the method using bar codes? Why? 8

9 7. What virus family is the SARS virus most closely related to? 8. What animals do scientists think are the most likely sources of SARS? 9

10 This activity addresses the following Next Generation Science Standards and Common Core State Standards for high schools. Next Generation Science Standards Standards HS-LS1 From Molecules to Organisms: Structures and Processes: HS-LS1-1 HS-LS3 Heredity: Inheritance and Variation of Traits: HS-LS3-1, HS-LS3-2 HS-LS4 Biological Evolution: Unity and Diversity: HS-LS4-1 Science and Engineering Practices Asking questions (for science) and defining problems (for engineering) Constructing explanations (for science) and designing solutions (for engineering) Engaging in argument from evidence Obtaining, evaluating, and communicating information Common Core State Standards ELA/Literacy Literacy in Science and Technical Subjects (Grades 11 and 12): RST , RST Writing (History/Social Studies, Science, and Technical Subjects): WHST , WHST , WHST Speaking and Listening (Grades 11 and 12): SL Mathematics Standards for Mathematical Practice: MP.2 Crosscutting Concepts Patterns Cause and effect: Mechanism and explanation Structure and function 10