Social Impact: DNA Dragnets
by Ronee Yashon, J.D.

The Social Impact section is your opportunity to work through an ethical, legal, or social question that the research we're reporting on has raised. Many times, these questions are so new, it's difficult to pose them clearly, much less answer them easily.

Australian Policemen conduct a DNA Dragnet (AP/Wide World Photos)

For this issue of Snapshots, the question is, How broadly should police be allowed to cast a "DNA dragnet" while investigating a crime? As the cost of doing DNA-identification analysis comes down and the speed increases, interest in using DNA chip technology to sift through large groups of people in a search for suspects will surely grow.

First, read the scenario below. Then, pick a question from the list and work through the Decision Form that follows. The form is designed to mimic the kind of back-and-forth discussion the society at large will go through as people attempt to reach consensus on this and other questions that biomedical research raises.

(NOTE: This scenario is fiction. The names, places, and events are all imaginary.)

September 9, 2003. Peyton County Police Detective John Franklin has a very hard case on his hands. Two women, Mary Adams, age 24, and her sister Gloria Adams, age 17, were brutally murdered while camping near Yorktown Springs, a small town in his jurisdiction. The crime occurred at night in Big River State Park, during a heavy rain. Franklin can find no witnesses, no footprints, no murder weapon, no tire tracks, and no fingerprints. He has only one good lead-bits of skin under the fingernails of Gloria Adams, almost certainly from the killer. A DNA match to this tissue would conclusively link a suspect to the crime.

But where should Detective Franklin start? He has no suspects. However, just last week a company called Gene Identification Systems sent him a brochure about a new product. It uses a device called a DNA microarray to do DNA-identification analysis very quickly and for relatively little money.

Because Yorktown Springs is so small, Franklin thinks he could use the new technology to carry out a "DNA dragnet." He could ask all 2,143 adult residents to give a DNA sample-just a Q-tip rubbed gently inside the cheek-and test them all. With Gene Identification's microarray technology, he could do all the testing for less than $20,000, and get the results in just 3 days. DNA dragnets have been used frequently in Great Britain, and they sometimes get results.

Franklin decides to try. He makes a list of all the people in the county over age 17. He contacts them all, and asks each to provide a sample voluntarily.

1. Imagine you live in Yorktown Springs, and Franklin asks you for a sample. What would you do?

2. After Detective Franklin sends out a letter to all adults in the area, he begins testing. The 238th person on the list, a man named Irving Tomston, doesn't respond to letters or phone calls. What should Franklin do?

3. After processing samples from all Yorktown Springs residents over17 years of age, Franklin doesn't find a match. What should he do?

4. A match is found in the samples taken in the dragnet. At trial, the defense argues that the evidence should not be admitted. What should the judge do?

5. After the testing, Franklin announces that his department will put all the DNA profiles collected in the dragnet into a computer database for future investigations. Should he be allowed to do this?

Decision Procedure

  1. Choose which question you will address.
  2. List three possible answers to this question.
  3. Come to a decision about which of these answers is best, and circle that number. List three reasons why this is the best answer.
  4. List three reasons other people might not agree with your best answer.
  5. With those counter arguments in mind, why is your answer still the best?
  6. Identify at least three people or groups with a stake in the question, and state how they would be affected by your solution.
  7. Give two possible outcomes for the country if your solution was put into practice.

A Few Fast Facts About DNA Dragnets

  • Although the scenario presented here is fictional, DNA dragnets have been employed in other countries, including the United Kingdom and Australia. For example, on January 1, 1999, a 91-year-old woman was raped in her home in Wee Waa, a small town in New South Wales, Australia. The police had no good leads. In April 2000, police asked all men between the ages of 18 and 45 living in and around the town to give a saliva sample for testing. Stephen Boney, a 44-year-old laborer, was one of over 600 men who gave a sample for analysis. Ten days later, before his sample was analyzed, Boney confessed to the crime. He pleaded guilty at his trial on July 11, 2000, and now awaits sentencing.
  • Taking DNA samples from many people in a specific area is called a mass DNA screening or a "DNA dragnet." As the cost of doing DNA analysis comes down, interest in this tactic will surely grow.
  • Currently, DNA identification is labor intensive and costs about $50 per sample. DNA microarrays could dramatically reduce this cost, however, making it more practical to test a lot of people quickly.
  • DNA-identification analysis reveals nothing about any physical traits a person might have. It's useful for identification only.
  • To do DNA identification, labs analyze a set of DNA sequences called short tandem repeats (STRs). As the investigator analyzes more STRs, the chance of a random match goes down. The FBI has identified a standard set of 13 STRs for DNA identification. The chance that two people are identical in each of these 13 STRs is virtually zero.
  • DNA testing could conceivably reveal much about person's physical characteristics. If the original sample is also kept, not just the identification profile, an enormous amount of information about an individual's genetic traits could be acquired by performing other tests.

On the Web
If you like this approach to bioethics, Ronee Yashon has two books full of case studies.

Lawrence Kobilinsky has an interesting opinion piece on the limits of DNA collection 00/02/28/kobilinsky0228_01.html

Here’s an opinion decidedly against the use of DNA Dragnets.

The National Institute of Justice, through the National Commission on the Future of DNA Evidence, has produced an excellent summary of where forensic DNA testing technology is headed.

A search on any good Web search engine (Yahoo, Google, etc.) will turn up lots more.Try “Mass DNA Sreening” or “DNA Dragnet.”