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DNA Identity (April 11, 2003, One)

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Program Summary

It’s not so elementary, my dear Watson. Things have come a long way since the days of Sherlock Holmes, when the only tools a detective had were a sharp eye and a logical mind. Now police and scientists have a vast array of technological tricks at their disposal—autopsy, fingerprints, blood typing, dental records, ballistics, chemical and fiber analysis, x-rays, computer modeling, forensic entomology (study of insects), and much more. One technique which has dramatically changed the field of forensic science is DNA identification.

Like fingerprints, every human has unique DNA; unlike fingerprints, which can be surgically altered, you can’t change your DNA. Fingerprint evidence can be too fuzzy to be read well, but DNA patterns speak out loud and clear. They have convicted thousands of criminals and exonerated innocent people. The advent of DNA testing has enabled many prisoners who were serving long jail terms to have their convictions overturned after DNA revealed that they didn’t do it after all.

DNA fingerprinting has also been used extensively to identify human remains, solving long-standing mysteries. Czar Nicholas II of Russia and his family, executed by the Bolsheviks, were finally identified and laid to rest, as were the remains of an anonymous soldier from the Vietnam conflict, interred in Arlington Cemetery’s Tomb of the Unknown Soldier. It was indispensable for identifying victims of the September 11, 2001, bombing of the World Trade Center, when scientists sometimes had almost nothing to work with. Experts are confident that if Saddam Hussein’s body is ever recovered, DNA testing will bring an undeniable conclusion one way or the other.

DNA has had an enormous impact on anthropology as well. Mummies and skeletons that were mute for hundreds and thousands of years now tell us if they are male or female, healthy or diseased, related to each other, even what they had for dinner, helping anthropologists reconstruct the details of long-gone civilizations. If only they’d tell us where they hid the treasure ...

Guests

Max Houck, projects director at the Forensic Science Initiative of West Virginia University in Morgantown, West Virginia

Related Links and Resources

Columbia University, 21^st C: “DNA as a Forensic Instrument”
Miami Dade Police Department: The Evolution, Practice and Future of the Use of Science in the Administration of Justice
National Research Council: The Evaluation of Forensic DNA Evidence
ToledoBlade.com, April 9, 2003: “Saddam Mystery Likely To Be Solved By DNA, Scientists”

For Discussion:

• What are some sources of DNA?
• Why is DNA identification so accurate?
• How does nuclear and mitochondrial DNA differ?
• What do crime scene investigators do? Are they different from detectives?
• What do forensic pathologists do?
• What are some other tools that forensic scientists have to solve crimes and mysteries?

Activities

Use your ima-gene-ation! Last Flight of Bomber 31: Identifying Remains with DNA, a PBS “NOVA” broadcast, explains the differences between nuclear and mitochondrial DNA and how each are used in identification. An interactive feature demonstrates how DNA can help trace a family tree.

The name’s Friday... Your DNA I.D. Card explains how DNA is made into a readable image. Students can then create a virtual DNA fingerprint and match it to a suspect at Create a DNA Fingerprint at NOVA Online’s Killer's Trail. This site follows the efforts of Sam Reese Sheppard, son of Dr. Sam Sheppard, to clear his father’s name in the murder of his wife.

Tricks of the trade. A number of good forensic science lesson plans can be found on the Internet. These are just a few:

• DiscoverySchool.com: Forensic Detectives: Who Did It? Students use forensic skills to solve a fictional classroom crime, from evidence collection to analysis to hypothesizing. Thoughtful discussion questions, links to other sites.
• Forensic Science Activities adds lip prints and handwriting analysis to the mix and presents several short scenarios to the students.

Dick Tracy, Jr. Who Dunnit? (cyberbee.com) is meant for a younger audience, but it’s still fun and brimming with good information. Powder analysis, dental evidence, and foot print activities are used along with other tools to solve a cute crime mystery. A Thinkquest site, Evidence: The True Witness, is difficult to navigate—many script errors; some pages can only be accessed through the “Tour” feature; and whatever you do, don’t click on the Home button. However, there’s a great game in which the student role-plays a detective investigating a kidnapping (take the tutorial first), and another section discusses careers in forensic science. There’s also an extensive list of links.

Return of the mummy... DiscoverySchool.com’s Forensics: Who Killed the Iceman? [Link updated August 6, 2007] is a lesson in forensic anthropology, examining the true story of the discovery of a frozen, 5,300-year-old man in the Alps. Students will gather evidence to make a decision about how the iceman died. The lesson plan also compares the European ice mummy to that of young Incan girl found in the Andes Mountains of South America. At Andes Expedition: Search for Inca Secrets, students can follow a virtual autopsy.

For information and activities about forensic science, visit Science Friday Kids’ Connection’s Ballistics Fingerprinting from October 2002.

Use the search box below to perform a Google search within any of the specifc sites or general domains mentioned in this Activities section.

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