". . . clinical laboratories must meet higher standards to be allowed todiagnose strep throat than forensic labs must meet to put a defendanton death row."Medical geneticist Eric Lander, now director of MassachusettsInstitute of Technology's Whitehead Institute of BiomedicalResearch, made that put-down of forensic DNA typing practices fiveyears ago in Nature (June 15, 1989). That was then.Now: "The DNA fingerprinting dispute has been laid to rest," Landersaid. That is the headline over a four-page commentary he wrote intoday's Nature jointly with his former opponent, Bruce Budowie, aforensic scientist at the FBI Academy in Quantico, Va.Lander served on the 12-member, blue-ribbon panel of the NationalResearch Council (NRC), which in April 1992 issued a definingreport on DNA technology in forensic science.The three-year study was chaired by pioneer human geneticist VictorMcKusick, who said at the time that DNA fingerprinting is "a verypowerful method of personal identification, because except foridentical twins, there are no two people on the globe who haveprecisely the same DNA patterns."The NRC report also stated that the Justice Department's FBI "lacksexpertise in quality assurance and quality control in molecularpopulation genetics," and "may be perceived as an advocate in theapplication of the technology."Today, three years later, Lander and the FBI's Bruce Budowie wrotein Nature, "As co-authors, we can address these questions in aneven-handed manner. Budowie was one of the principal architects ofthe FBI's DNA typing program, whereas Lander was an early andvigorous critic of the lack of scientific standards."In L. A. Courtroom: Molecular Genetics 101As his response to anticipated media inquiries, Lander dictated thefollowing one-liner: "In view of the ongoing proceedings in severalprominent criminal cases, I feel it is best to confine my comments tothe text of the Nature article."That article began by observing that coverage of the O.J. Simpsontrial "will probably feature the most detailed course in moleculargenetics ever taught to the U.S. people."Its authors went on to point out that "This bold experiment in publiceducation should, in principle, be a cause for rejoicing amongscientists. The catch is that the syllabus is being prepared byattorneys whose primary roles are as adversaries; the likely result isconfusion."Compounding that confusion in the courtroom are warnings by thenews weeklies that DNA fingerprinting remains "controversial."To counter those caveats, the authors add up ". . . by the middle ofthis year [1994] . . . more than 400 scientific papers, 100 scientificconferences, three sets of technical guidelines from the TechnicalWorking Group on DNA Analysis Methods, 150 court decisions and,importantly, [the NRC report] released in 1992." Given this flood offindings, Lander and Budowie ask "whether it is time to declare thegreat DNA fingerprinting controversy over."Answering their rhetorical question, the authors state: "The DNAfingerprinting wars are over," and explain that their goal in thiscommentary "is to correct the lingering impression to the contrary,"especially in the problem of population genetics, which underlies thebasic interpretation of forensic DNA findings.They explain: "If DNA analysis reveals that two samples match atthe loci tested, the final step is to estimate the frequency of theshared genotype in the general population, which indicates theprobability that a randomly chosen person would carry thisgenotype."Harking back to those antediluvian times in the late 1980s, Landerrecalled one commercial lab that reported a frequency probability ofone in 738 trillion. The commentary goes on to analyze the problemsthat arose in setting population and subpopulation baselines derivedfrom genetic variations in racial and ethnic groups. The solutionreached by the NRC report, called the "ceiling principle," the authorswrote, "gave the benefit of every conceivable doubt to thedefendant, so that it could withstand attacks from the most stubbornand creative attorneys."Under the ceiling principle, "A four-locus match performed byforensic labs could still provide odds of 6.25 million to one. If thiswere not enough, two additional loci could increase the odds to morethan one in 15 billion."But Lander and Budowie also point out that ". . . a jury needs toknow only that a particular DNA pattern is very rare, to weigh it inthe context of a case: the distinction between 104, 106, and 108 isirrelevant in the case of suspects identified by other means.""Since the NRC report," the commentary notes, "U.S. courts haveunanimously accepted the technical reliability of DNA evidence,both in principle and in practice."As if to preempt lingering opposition among scientists and jurists,the Nature commentary's subhead reads: "Two principals in theonce-raging debate over forensic DNA typing conclude that thescientific issues have all been resolved." n

-- David N. Leff Science Editor

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