In this activity, students learn how DNA analysis is changing the way we fight crime and disease. Students begin by exploring the use of DNA fingerprinting in criminal investigations. They conduct a Web activity that teaches them how DNA fingerprinting is done. Then, working in teams, they examine and interpret the DNA fingerprints of a group of individuals. Next, students review the location and role of DNA in the body. They learn how a single mutation in DNA can affect health -- for example, how a mutation in the gene that controls red blood cells can result in sickle cell anemia. Finally, students learn about the significance of the Human Genome Project and the promise it holds for curing disease.
- Understand how DNA fingerprinting can be used in criminal investigations
- Interpret DNA fingerprints
- Explore other uses for DNA fingerprints
- Understand where DNA is located and the role it plays in the body
- Recognize how mutations can cause genetic disorders
- Learn about the purpose and work of the Human Genome Project
- Two to three class periods
- Forensic DNA Analysis Video
- Create a DNA Fingerprint Interactive
- DNA Fingerprint Photos Document
- Journey into DNA Interactive
- A Mutation Story Video
- Human Genome Project Video
- Sets of the DNA Fingerprint Photos pasted on cards, one set per team of four students
- Optional: How DNA Evidence Works Document
Before the Lesson
- Make copies of the DNA Fingerprint Photos document; cut and paste the photos on cards. Make one set of cards for each team of four students.
- If necessary, review the concepts of DNA replication and protein synthesis using How DNA Replicates video and From DNA to Protein video.
1. Show the Forensic DNA Analysis video. Discuss the following:
- How was the DNA evidence used to prove that Dr. Sam Sheppard did not murder his wife?
- Why wasn't this evidence used when the case first went to court?
- If you were a juror on this trial, would you be convinced by the DNA evidence?
2. Explain that DNA is playing an increasingly important role in criminal investigations. Tissue evidence is now routinely collected during these investigations in hopes that it will provide genetic clues linking suspected criminals to crimes. Have students explore the Create a DNA Fingerprint Web activity to learn how DNA fingerprinting is done.
3. Give each team of students a set of the DNA Fingerprint Photos. Ask them to interpret the fingerprints and compare their answers to those of other teams when they are finished. Provide a key of correct answers. Or, ask:
- Do any of the suspects have DNA patterns similar to the crime scene sample?
- Can you pick out which set of twins are identical and which are fraternal?
4. If time allows, have students read the How DNA Evidence Works Document and discuss.
- What are some other uses for DNA fingerprinting?
- Why is DNA fingerprinting called a "numbers game"? What increases the accuracy of DNA fingerprinting?
5. Ask students:
- What is DNA? Where is it found in the human body?
6. Have students do the Journey into DNA Web activity. Then ask:
- What is the role of DNA in the cell? In the human body?
7. Show the video A Mutation Story. Discuss the following:
- How does a mutation change the DNA structure?
- How does the sickle cell mutation affect the function of red blood cells?
- How can a mutation be harmful in one environment and helpful in another?
8. Explain that scientists have been working to learn all the DNA sequences of human genes so that they can better understand human disease. This research is called the Human Genome Project. Show the Human Genome Project video and discuss the following:
- What are some of the strange and unexpected things that were discovered when scientists analyzed the human genome?
- Why do scientists compare the DNA of bananas, worms, fruit flies, and humans? How could this information be helpful?