Neither History Nor Science

Patricia Cornwell's nonfiction attempt1 to name serial killer Jack the Ripper reads more like fiction than fact. Cornwell has identified Walter Sickert, a well-known Victorian painter, as Jack the Ripper based almost solely on two observations: 1) that Sickert was a nighttime wanderer of London streets during the Ripper's spree, and 2) that Sickert painted spooky scenes reminiscent of Ripper locales and victims. Diehard fact-collecting Ripperologists will gasp at the editorialized renderings of Jack's crimes. Although a list of primary and secondary sources for Cornwell's distillation of history will be found in the back of the book, in-text citations are absent. What will the serious student of the massive body of Ripper documentation learn from the following quote? "This morbid means of transportation was one that Walter Sickert would have seen had he lingered in the dark and watched his victims being carried away. It must have been thrilling to spy on a constable huffing and straining as Mary Ann Nichols's almost severed head lolled from side to side while the big wheels bounced and her dripping blood speckled the street." This is not history, but it may be entertainment. Cornwell does quite a successful job of setting the stage in gloomy, dirty, crime-ridden London, and describing the forensic world of the 1880s. Digressions into autopsies of the day, crime scene investigations, and comparisons with how forensic science has progressed in 100 years do provide a tasty base for otherwise weak speculations about Sickert as Ripper. While being in no way convinced that Cornwell was on the right track about this long-standing mystery, as a forensic scientist, I was fascinated with some factual, apparently well-researched descriptions of the era. The book also is not science. Cornwell posits a penile deformity in Sickert that led to misogynistic fantasies and murderous intent. But the Sickert literature on this medical problem must be slim, because the "could have," "would have," "might have," and "must have" literary machinations reach a peak in this section of the book. In spite of this, we do learn that Sickert had several wives and may have fathered children. Particularly frustrating to readers with any knowledge of genetics will be the small sections covering some DNA testing pursued by Cornwell. Not surprisingly, nuclear DNA testing on swabs taken from dozens of Sickert and Ripper letters was unsuccessful. The author then moved on to a method known for its success in capturing ancient DNA: mitochondrial DNA (mtDNA) analysis. This being my own area of scientific specialization, I alternately laughed and winced over descriptions of this testing. Tragically, given the current popular belief that DNA reveals all, the average reader will not realize that these results are meaningless or at least glaringly incomplete. As a general rule, touched objects, as opposed to hairs and bones that can be cleaned before testing, are poor candidates for mtDNA testing. To complicate matters, modern intact DNA, and not DNA authentic to the sample, may be preferentially captured by current techniques. A century-old scrap of paper is a palimpsest of DNA from the many people who have handled it, even if they deposited only a single skin cell. Cornwell appreciates this, pointing out that almost all the samples showed the presence of mtDNA mixtures from two or more individuals. Only two items of 55 tested: A letter from James McNeil Whistler (a mentor of Sickert) and a partial stamp from a Ripper letter gave single-donor mtDNA sequences. A comparison with mixture sequences from five other items (Sickert and Ripper letters) indicates that the nucleotide substitutions that were in the single-source Ripper stamp sequence were also present in these five items. Unfortunately, a conclusion that these samples were therefore from the same person is invalid, because mixtures can indicate that many dozens of possible types are present, and not necessarily the one being compared; currently, cloning may be the only validated way to sort out the components of an mtDNA mixture. Especially unfortunate are the analyses from swabbings of Sickert's painting coveralls. Cornwell points out that nucleotide substitutions at mitochondrial positions 73 and 263 are present and that these two substitutions are also present on the Ripper single-source stamp. Did no one tell her that these substitutions are found in roughly 50% and 99% of all Europeans, respectively? Most frustrating of all is that no Sickert mtDNA profile was available for comparison to the Ripper stamp. Given the technology-rich state of genealogical research, it is hard to believe that a living distant maternal relative of Sickert cannot be traced, even many generations removed. Although Cornwell has not overstated the probative value of her DNA testing--indeed, she expresses her own frustration at the unclear outcome--she is guilty of publishing scientific findings by press release, that is, in the popular literature. This kind of data presentation would allow a modern defense attorney for Walter Sickert to have great fun at her expense. Other fascinating historical genetic analyses, such as the identification of the Romanovs, Jesse James, and Neanderthals, were legitimized by peer-reviewed publication of the laboratory findings. The data then spoke, loudly, for themselves. Terry Melton, PhD, is president, CEO, and lab director of Mitotyping Technologies, State College, Pa. 1. P. Cornwell, Portrait of a Killer: Jack the Ripper Case Solved, New York: G.P. Putnam's Sons, 2002.

Neither History Nor Science

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