THE ULTIMATE CLUE, MY DEAR WATSON: DNA FINGERPRINTING
Grades 9-12

Students learn practical applications of DNA profiling in today's forensic science and the future's many possibilities. While viewing the video, students delve into the problems of extracting ancient DNA from fossils. These molecular biologists use DNA profiling to sequence pieces of the dinosaurs' genome. After viewing the video, students will simulate DNA profiling with electrophoresis gel to solve a possible baby mix-up at the hospital.

NOVA: The Real Jurassic Park

Students will be able to:

• Explain the steps of DNA Profiling
• Describe the possible usefulness of DNA Profiling to our society
• Contrast extracting ancient DNA from fossils to modern DNA from blood and other cells of organisms.

Per group of two:

• Copies of the lab "Will the Real Baby Smith Please Speak Up!"
• Scissors
• Glue or tape

To prepare students for the video, explain the steps of extracting and profiling DNA. Explain how DNA is extracted and isolated from cells. Cell membranes are lysed with detergent. The detergent will dissolve the lipid component of the cell membrane and expose the protein and nucleic acids. DNA must be extracted at a temperature range of 50°-60° Celsius. Temperatures exceeding 60° C may denature the DNA. DNA must then be placed in ethanol because it is soluble in aqueous solutions.

For an interesting demonstration of extracting DNA, purchase 1 DNA spooling Kit. This laboratory activity allows students to extract DNA from salmon sperm. The students will add ethanol alcohol to the sperm solution and precipitate DNA by spooling it onto a stirring rod. The students are delighted. Request Sigma product D-8666: 1 kit $18.90 from: Sigma Chemical Company PO Box 14508 St. Louis, MO 63178-9916 (800) 325-3010)

Explain how DNA is cut with restriction enzymes, run through an electrophoresis gel, and probed with a radioactive substance, which appears on the film. Many different restriction enzymes are available, and scientists choose the one that will cut the DNA in the appropriate place in the sequence. Each person has a slightly different sequence and when probed with radioactive substances will produce a unique set of bands.

Ask the students for possible uses of DNA profiling. Have students bring in news articles of recent court cases that use DNA fingerprints as evidence. Another use of DNA profiling is to locate genes in our human genome. Once these genes are found, they can be isolated and possibly inserted into people whose genes are not functioning properly. Discuss the possibilities with cutting out dysfunctional genes and inserting functional ones to cure a disease. If there is time, distribute "Designer Genes" worksheet and hold a mock trial or debate about the moral implications of such genetic engineering. Discuss probability, a branch of math that predicts the occurrence of chance events. Give students statistics for DNA testing in various court cases and have them predict the chances of two people having similar bands.

To give students a specific responsibility while viewing, have them write down each hurdle scientists must overcome to extract and sequence a dinosaur's DNA (4 billion base pairs!) Ask if they believe Jurassic Park could become a reality some day.

BEGIN the NOVA video "The Real Jurassic Park". PAUSE when Jeff Goldblum says, "Jurassic Park has left me wondering if we will ever see dinosaurs in the zoo someday." Ask the students the same question again, "How many of you believe that someday Jurassic Park could become reality?" RESUME the video.

PAUSE after Michael Crichton speaks about his book. Discuss what is meant by a genetically engineered dinosaur. RESUME the video.

PAUSE after Step 1 Find Dinosaur DNA. Contrast uses and accessibility of obtaining DNA from modern living organisms to that of dinosaurs' fossils. As students watch the rest of this segment, have them write down all problems that must be overcome just to extract and assemble the DNA from dinosaur fossils. (Small organisms the size of a pin-point, range of species of dinosaur DNA in insect's stomach, trying to figure out which species the DNA came from, and if found in the bones, they must be well preserved) RESUME video. PAUSE when Poinar Jr. holds up the gel sheet and points to the DNA bands. Explain that this is a DNA profile film that was discussed in previewing. RESUME the video. PAUSE after the color of ancient DNA and modern DNA is shown when the female scientist takes them out of the freezer. Discuss the viability of the DNA that is only 13,000 years old compared to 100 million years old dinosaur DNA. Ask "What do you think happens to DNA over one million years?" RESUME the video.

STOP the tape after John Horner shows the jaw of a rapter and discusses manipulating eggs and sperm. Discuss on and off switches for genes in our bodies. Tie this into prenatal care and how important it is to allow off genes to stay off and on genes to come on. Drugs and alcohol can effect this delicate balance and cause diseases or deformities. On a positive note, genetic engineers may learn to turn on genes that code for important proteins such as insulin. This could rid a person of diabetes.

To prepare students for the lab activity " Will the Real 'Baby Smith Please Speak Up" review the processes of DNA extraction and DNA profiling. Discuss how DNA is separated in gel solutions. Gel electrophoresis is a technique which separates charged particles such as nucleic acids by running them through an electrical field. The DNA segments (which were cut by restriction enzymes) migrate toward the opposite charge at the other end of the gel. The smallest fragments can travel or migrate through the gel the fastest. A radioactive probe is then placed on the bands and comparisons or conclusions can be drawn as to whose DNA fingerprint is more closely related.

Tell the students they will be simulating the process of DNA profiling in the activity, "Will the real baby Smith Please Speak Up!" Explain that a simulation allows students to understand each step of DNA profiling. Students will simulate cutting the DNA with enzymes, running it through the gel, attaching radioactive probes, and developing the film to see bands.

Have students predict the impact of biotechnology on their future and place their ideas in a time capsule to be opened at their 10 year reunion.

Invite a genetic engineer into your classroom to share recent research being performed. It is possible that he/she could bring in equipment to show how the process of electrophoresis gel is used to analyze DNA.

Visit your local forensic lab to learn how DNA fingerprinting is useful in solving crimes.

Have students write to local judges asking if DNA profiling has ever been used to help solve crimes in their immediate area.

LANGUAGE ARTS/SOCIAL STUDIES: Finish viewing the NOVA tape " The Real Jurassic Park". Invite the students to express their opinions of bioengineering using the debate,"Should dinosaurs be brought back to life and placed in modern society." Have students write arguments to support their position. Share ideas the next day in class to spark a debate. Have students prepare a combined argument to present to the Environmental Protection Agency. If some students are unsure, have them represent the Environmental Protection agency to make the final decision based on the arguments presented by classmates. ("Exploring Jurassic Park", The Science Teacher , November 1993, Simmons and Wylie)

ART/ENGINEERING: Have students draw or create a three dimensional model of a dinosaur zoo for tourists to visit. Make sure the students research appropriate habitat, food sources, space for size of dinosaur etc. Students could use facts from Michael Crichton's book Jurassic Park for guidelines.

SCIENCE/SOCIETY: Take students to the library and look up recent articles on breakthroughs in the Human Genome Project. Such diseases as Alzheimer's, heart disease, and many other genetically inherited disorders are being mapped by scientists internationally. After reading the articles, students could predict the outcomes of such technology for the year 2100. Relate this to vaccines and medicines that were not around 100 years ago.

Purchase SCIENCE SLEUTHS videodisc from VIDEODISCOVERY and have students solve the mystery of the Forgotten Triplet. This is an interactive videodisc that allows students to witness interviews, look at documents, and see results of scientific tests such as DNA profiles to determine which person could be the long lost triplet to share the inheritance.

Master Teachers: Suzanne Asaturian and Cindy Vernon