It's an intriguing assertion, and one that grabbed headlines at sites like ABC News and NBC News—that more than a century after Jack the Ripper terrorized London, the serial killer had possibly been unmasked. Too bad it's bogus, at least according to a slew of experts. Here's the chain of events: Jari Louhelainen of Liverpool John Moores University and David Miller of the University of Leeds published a case report in the Journal of Forensic Sciences based on an analysis of victim Catherine Eddowes' silk shawl, which is purported to have been stained with blood and semen. The researchers call it "the only remaining physical evidence linked to these murders," and they tested it for mitochondrial DNA, or mtDNA, which a child inherits from his mother. They said they found a match to a living relative of one of the main suspects, Polish barber Aaron Kosminski, and call their study "the most advanced genetic analysis to date." Four reasons why scientists are extremely skeptical:
- The provenance of the shawl is far from ironclad. Ars Technica reports even the authors write it is "purportedly linked" to Eddowes, but that's a shaky assertion at best. A 2014 article on the shawl at the Conversation explained that the shawl is said to have been collected by a police officer named Amos Simpson—who was posted well outside London. Experts had previously dated it to the Edwardian era. "If that holds, it could not have been at the murder scene," the Conversation notes. Geneticist Adam Rutherford tweets, "The provenance of the shawl is comical and would not be considered believable by even the most lazy historian."
- The shawl was horribly mishandled. More from Rutherford: "Even if it was really present at the murder scene, and bizarrely was kept (none of Catherine Eddowes' other clothes were), and kept unwashed, the way it has been handled since would render DNA analysis cripplingly problematic." Ars Technica writes that mishandling involves people holding it without gloves—people including Kosminski's descendants.
- As far as DNA goes, Science speaks with an mtDNA expert who explains its analysis "can only exclude a suspect." Science translates: "The mitochondrial DNA from the shawl could be from Kosminski, but it could probably also have come from thousands who lived in London at the time." Further, since Kosminski was a man, he wouldn't have passed on his mitochondrial DNA.
- And the researchers didn't include highly detailed genetic results. Instead of publishing the specific genetic variants they zeroed in on, they show a graphic with overlapping colored boxes to indicate matching DNA sequences. The authors' reasoning is that the UK's Data Protection Act curtails their ability to publish the genetic info of Eddowes' and Kosminski's modern-day relatives; a forensic scientist who spoke with Science saw no such privacy risk. "I wonder where science and research are going when we start to avoid showing results but instead present colored boxes," Walther Parson said.
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