Genetic Witness: Science, Law, and Controversy in the Making of DNA Profiling

Chapter 8: The DNA Wars Are Over

173 When Americans think about controversies over DNA evidence that have taken place in this country, Castro, Yee, and the National Research Council probably do not figure too heavily in our collective memory. Rather, visions of white Ford Broncos, bloody gloves that don’t fit, and footprints from“ugly-ass”Bruno Maglia shoes dominate our perceptions of the use of DNA in the criminal justice system. Who can forget the low-speed highway chase, Judge Ito, nonstop news coverage of the“Trial of the Century,”the theatrics of the highly paid legal“Dream Team,” and the racially charged reaction to the not-guilty verdict? Justified or not, the criminal trial of ex-football star and actor Orenthal James Simpson looms large over the history of DNA profiling. Despite the publicity that the DNA Wars received in the run-up to the trial, the Simpson case was in many ways the denouement rather than the climax of the disputes that have been described in this book. Although the second NRC report had not yet been written, the debates over DNA profiling were essentially over when Simpson’s criminal trial began in January 1995. The validity of DNA profiling as a technology was never actually questioned by Simpson’s defense team, even though he had hired Barry Scheck, Peter Neufeld, and William C. Thompson to attack the forensic evidence in the case.Instead,the defense focused on the potential for accidental contamination and police malfeasance during the collection, processing, and storage of biological samples at the crime scene. There was no one event or document that caused the debates to end in the months leading up to the trial. Rather, the legal and scientific debates over DNA evidence were extinguished slowly through a combination of FBI initiatives, judicial decisions, federal legislation, a very shrewd public relations move by former defense witness Eric Lander and the FBI’s Bruce Budowle, technical changes in RFLP-based DNA profiling, as well as the development of an entirely new method for creating DNA profiles called short tandem repeat analysis, or STR for short. The DNA Wars Are Over c h a p t e r 8















Chap-08.qxd 6/28/07 10:09 AM Page 173 But not everybody involved in the debates over DNA typing believed that all of the problems that had emerged over the previous five years had been resolved. One of the most important factors in the end of the disputes was that the issue of population substructure received so much attention in the wake of the Yee trial and the problematic ceiling principle, that it came to represent almost the entire debate in the popular press, the academic community, and the courtroom. Additionally , in the case of the population genetics debate, defense witnesses provided a clear challenge to the FBI: they called for the examination of racial groups for population substructure. While meeting this challenge, the FBI succeeded in making population genetics the dominant issue to be resolved. In their demands for a second NRC report, the FBI did not ask the National Academies to resolve questions from the first report that it did not think were legitimate (e.g., how to set up a blind proficiency testing scheme or how to estimate laboratory error). The FBI wanted a document that courts could point to as evidence that no controversy existed over DNA profiling, and this was largely what they got. When the second NRC report was finally published in 1996, the kinds of social and political compromises made by the first committee were gone. As its executive summary noted, the recommended procedures for calculating the probability of a random match were based solely on population genetics and statistics—the two disciplines that critics of the first report complained were missing. The most important conclusion of the second NRC report was that recent empirical studies of allele frequencies in subpopulations conducted by the FBI had rendered unnecessary the use of the ceiling principle to limit allele frequencies.1 They recommended that when the subpopulation of the evidence sample is known, the product rule should be used with the allele frequencies for that specific subpopulation .2 If the racial group of the donor is known, but not the subpopulation, then allele frequencies from the reference database for that racial group should be applied along with correction factors for the amount of overall inbreeding (i.e., nonrandom mating) within that racial group...