DNA Doubts DNA testing has changed the criminal justice system. Since 1989, hundreds of people have been exonerated of crimes they didn t commit, and tens of thousands of people have been cleared as suspects after being wrongly accused. However, DNA testing is not perfect. It can also lead to false convictions and other negative consequences. Analyze and synthesize the information in this lesson to write a fiveparagraph essay explaining the problems with DNA testing.
Reading Passage Read and annotate the extract from an article by Laurie Meyers titled The Problem with DNA Forensic evidence increasingly includes genetic fingerprinting, but researchers worry that juries may put too much stock in the results from Monitor on Psychology. Original Passage Since the advent of DNA testing, it's solved cold cases, connected crimes committed in different jurisdictions and even freed innocent men from death row. Genetic fingerprinting has in many ways revolutionized forensic science and is often the best weapon in an investigator's arsenal. However, popular crime shows such as "CSI," "Forensic Files," and "Law and Order" make solving crimes and catching criminals look easy, particularly with DNA evidence. In reality, juries sometimes gloss over the possibility of lab mistakes and mixed evidence even the similar DNA of siblings which can all lead to false positives and land innocent people in prison. Since everyone's DNA except that of identical twins is unique, the chance of a coincidental match is often around one in 10 billion. This sounds really impressive, given that the population of the earth is about 6.5 billion. But one in 10 billion is a statistical probability of coincidence. In other words, it is not proof that only one person on the earth could have this profile. What's more, that number does not factor in other potential problems, such as lab errors, says psychologist William Thompson, PhD, JD, professor and chair of the School of Social Ecology at the University of California, Irvine. In the courtroom, jurors tend to think that match statistics such as one in a billion cover all possibilities for error. But they only refer to one area, such as the chance of a coincidental match, and there are other mitigating factors such as the chances of a false match, Thompson explains. In the glitzy labs of crime dramas, no one argues about whether the DNA is a match. The test results are final. However, in the real world, it's not so cut and dried. Lab technicians run a sample through DNA processing software, which produces an image similar to an EKG readout, with a series of lines with peaks and valleys. These represent the number of repeating DNA sequences at certain points on the genome. If the profile is taken from a single source of DNA, there's not usually much need for interpretation, explains Thompson. Errors are more common when the DNA is "mixed," meaning from more than one person or the evidence is degraded by time or improper storage, he continues. Then experts must try to separate out the different sources. Topic: DNA Testing MI: DNA profiling has become a great tool for crime solving Myth: Solving crimes is easy w/ DNA evidence popular crime shows MI: Juries might convict wrong guy lab mistakes, mixed evidence Concession: True, coincidental match is highly unlikely : However, the odds are only a statistical probability Restate: They don t guarantee 100% certainty of the match Addition: They don t allow for other potential problems like lab errors MI: Coincidental match is unlikely, but not impossible Says who? Jurors usually think the odds rule out all possibility for error MI: Odds are only odds, and there are other mitigating factors Crime dramas: Things are neat and clear Real world: Things might get messy and unclear MI: Errors are more common w/ mixed DNA (multiple or degraded source) Why? Because experts then have to separate out the different sources
Original Passage The people who are sorting all of this out often know who is supposed to "match," which can influence the process. "Analysts think they should know all about the cases and evidence instead of just evaluating in a blind way," says Thompson, who is also an attorney. "Almost no crime labs do blind scoring and they can often become emotionally involved, and this leads to bias." Many public and private labs periodically test technicians' DNA-matching proficiency, and publish the results. From looking at such tests in the 1990s, Koehler has estimated that labs produce false positives in one or two instances out of every 100 tested samples. Judges rarely arm jurors with this information, and sometimes ask them to decide which expert to believe based on highly technical testimony, says Thompson, who often serves as a trial consultant. He recently consulted on a case where the dispute over a match was due in part to confusion over whether there were two or three contributors to the DNA sample. "What does a jury do with that?" he asks. Jurors often get too much information, and not enough instruction on how to analyze it, says David H. Kaye, JD, a law professor at Arizona State University. For instance, in cases with good samples, probability estimates should be thrown out the window, Kaye says. "What do we care if it's one in one million or one in one sextillion?" he asks. "Why not have an expert say, 'It's my opinion that this came from the same individual?'" And while most of the time a match is a match, says Thompson, sometimes an overeager lab, a messy crime scene and a jury that's watched too much crime television can lead to a mistaken conviction. "They think they understand it better than they do," he says. MI: Analysts sorting things out may influence the result Analysts (wrongly) believe they should know about the cases, evidence (The right way is) They should just evaluate in a blind way (However) Almost no blind scoring emotionally involved bias Labs test their technicians DNA-matching ability and publish the results (According to an estimate of test results from the 199s) MI: Labs produce false positives for 1 2 percent of tested samples (!) MI: Judges usually don t provide jurors with enough information Jurors don t know how to handle highly technical stuff MI: Sometimes, (OTOH,) jurors get too much info w/o proper instruction Example In cases w/ good samples, we should just make it simpler for jurors Concession: DNA profiling results can usually be trusted MI: They might sometimes lead to a mistaken conviction, because of a) lab mistake, b) mixed sample, and c) jury overconfidence Further explains the meaning of a jury that s watched too much crime TV
Listening Track Transcript It now goes without saying that DNA profiling is the single most important development in the criminal justice system since fingerprinting. Like the fingerprinting revolution that preceded it, DNA profiling has led to the advent of several national databases. Yet, as is the case with many investigative tools, these databases have sparked a new controversy in the age-old tradition of tension between public peace and security and the rights of the individual. The arguments in favor of the databases all boil down to what we already know: they can help solve crimes. But today let s examine some of the criticism. One of the most troubling downsides to DNA databases has to do with the nature of DNA itself. This may surprise you, but DNA can be fabricated in a lab. What I mean by that is that an analyst with information about a genome sequence could make an artificial version of a DNA sample. In 2009, scientists at Nucleix, a research company in Israel, did precisely that. They were able to fake blood and saliva samples with artificial versions of DNA, using only information taken from a database. In other words, they did not even need a real sample of the DNA to replicate it. For anyone wary of law enforcement officers overstepping their authority, the implications are truly disturbing. According to Nucleix, zealous investigators could easily use databases to plant fake DNA evidence and, in theory, use it to convict anyone of their choosing. Science advisors for the American Civil Liberties Union, an advocate of individual rights, have asserted that it would be far easier to plant fake DNA evidence at a crime scene than fake fingerprints. And we all know how convincing DNA evidence is to juries. Now whether or not they believe a law enforcement agency would go to such lengths, a more immediate concern for most critics is personal privacy. This has already been the focus of some highprofile legal battles. One took place in the UK, which has one of the world s largest DNA databases. Up until 2008, British law enforcement agencies kept DNA samples of anyone who was arrested indefinitely, whether or not the person was convicted of a crime. This included children. In 2008, however, that practice was challenged at the European Court of Human Rights. One of the plaintiffs in the case, identified only as Mr. S, had been arrested at age 11, but soon after released without being charged. His lawyers argued that keeping his DNA information on file violated his right to privacy, and the court agreed. The decision did not stem the controversy, however. How UK law enforcement should address this ruling has yet to be fully settled, and the case continues to raise privacy issues in other countries. In Canada, France, and parts of the US, it is legal to use DNA in such databases for research without permission of the subjects who gave samples without even being charged with a crime. None of this has led to any serious calls to discontinue the collection of DNA samples, mind you. But we clearly have some work to do before we come to consensus on how exactly it should be done. Clearly, DNA profiling is a great tool for solving crime, like fingerprinting Also, like fingerprint databases, we now have DNA databases MI: DNA databases have caused a new controversy about tension between public security and individual rights Pros are summed up: DNA databases can help solve crimes Cons will be the focus of today s lecture Con #1 DNA can be fabricated in a lab Elaboration Analysts with genome info could cook up a DNA sample Scientists at Israeli research company Nucleix actually did it Truly disturbing implications Fake DNA evidence could be easily planted to convict someone Fake DNA evidence may be easier to plant than fake fingerprints Addition DNA evidence is so convincing to juries Con #2 (DNA databases pose a threat to) personal privacy Some legal battles have already started One famous case took place in UK DNA profiling was sued against in 2008 Plaintiffs included a Mr. S Lawyers argued that keeping DNA info violated privacy, and they won MI: 2008 UK ruling is NOT the end of the story In UK: How should UK law enforcement address this ruling? In other countries: DNA databases are used for research w/o permission Concession: DNA sample collection continues w/o serious challenge MI: We have work to do to reach consensus on how it should be done
Essay Planning Mind Map Use information from this lesson, your own experiences, or your independent research to create a mind map in response to the following prompt. What are some of the problems with DNA testing? DNA testing cannot rule out statistical anomalies. Describe some of the problems with DNA testing. DNA can be manufactured or faked in databases DNA testing still depends on reliable analysis and interpretation by lab technicians.