The Public Eye - Summer 2012 Edition

Forensic DNA Database Expansion: Growing Racial Inequities, Eroding Civil Liberties and Diminishing Returns, By Marina Ortega. Generations Ahead, December 2011. 19 pp.

http://www.generations-ahead.org/projects/dna-databases-and-justice

By Laurence D. Mueller

Generations Ahead, a social justice organization founded in 2008 that focused on the social and ethical implications of genetic technologies, shut down operations this past January when founding director Sujatha Jesudason left to start the CoreAlign Initiative at the University of California, San Francisco. One of its final efforts was "Forensic DNA Database Expansion: Growing Racial Inequities, Eroding Civil Liberties and Diminishing Returns," a report on the ever-expanding use of DNA databases for criminal investigations. (The report will remain available on the website for another three years).

 
United States databases now include the genetic profiles of millions of people. Managing Director Marina Ortega's study points to a number of key problems in such databases: the routine inclusion of people arrested but not convicted of crimes due to no standard requirement for expunging the DNA sample and profile of a person found innocent; the databases’ disparity in racial composition, which reflects the disproportionate arrests of Black and Latino men; and the potential for error in DNA testing.

Generations Ahead points out that the vast majority of social justice organizations have not engaged on this issue at all. In fact, these are not questions the scientific community has actively debated.

The Generations Ahead researchers operate on the premise that there might actually be a downside to having your DNA profile in a law enforcement database. Consequently, should some racial groups be subjected to these downsides more than others? Should innocent people ever be subjected to them? Forensic scientists often argue that there is no such downside for law abiding citizens, since the rarity of particular genetic profiles would make it impossible for an innocent person to be mistakenly matched to DNA found at a crime scene.

However, other scientists disagree with this point of view. DNA typing techniques, like any other scientific technology, can produce erroneous results. Indeed, two reports from different National Research Councils have acknowledged the significance of lab errors in forensic science.¹

Why is genetic matching so controversial? Aren't genetic profiles unique? While the chance of a coincidental match at thirteen genetic markers or loci (thirteen is the number used in most U.S. databases) is extremely small, many evidence samples today do not produce results at all thirteen loci. This is because the ability to amplify DNA in the laboratory has encouraged police to search for DNA in places they never would have examined 20 years ago. Evidence samples today may come from swabbing a door handle or light switch. Twenty years ago, the DNA typing techniques used would have yielded no results for these types of samples. However, the techniques used now permit the scientist to make additional copies of the evidence DNA in the laboratory, making it possible to detect profiles from samples so small they may only contain a half dozen cells.

Nonetheless, there are technical limits. The process of amplifying DNA in the lab may not perform equally well with all parts of the genetic profile. Consequently, many samples with extremely low amounts of DNA will yield only a partial profile. All other things being equal, a coincidental match to a partial profile is much easier than a match to a complete profile.

Most database searches do not require a precise match. The computer program that does these searches only looks for close matches (called moderate stringency
matches). Again, all other things being equal, a moderate stringency match is easier to obtain than a standard match.

As a scientist with 23 years of experience in forensic DNA typing, I can confirm the warnings Generations Ahead has raised within the social justice community. Mistaken identifications have already happened in database search cases. The investigation into the death of Jaidyn Leskie, a child who was kidnapped and murdered in Australia in 1997, produced DNA evidence believed to have come from the assailant. The investigators submitted this DNA profile to their local police databases. The samples seemed to match, but it was later determined that the person identified by the database search could not have been the murderer. A thorough coroner’s investigation produced evidence that the erroneous database match was probably the result of contamination in the Australian laboratory.

Most research on the population genetic theories used in forensic DNA typing have relied on small databases of a few hundred people. Today’s offender databases have millions of genetic profiles that offer the possibility of doing novel and powerful research relevant to forensic DNA typing. This research could test assumptions that are part of models used in forensic statistics, testing criteria for uniqueness declarations, and studying laboratory errors. These are the scientific areas that will eventually have significant implications for criminal investigations and civil rights.

The FBI, which controls access to the national database, refuses to let scientists use this data despite permission granted through the authorizing legislation. The arguments given against releasing data include privacy concerns and, according to officials, the excessive time required for law enforcement to provide such information. The FBI has also argued that other databases exist for these types of research programs, and that no worthwhile research can be done with these databases.²

These excuses are either wrong or have trivial solutions. Recently, forty one scientists and legal scholars have published a letter asking for access to these data.³ So far, the FBI has been steadfast in not heeding these calls.