Jack the Ripper ID undone by DNA error

"The Illustrated Police News" on display during a press preview for the exhibition "Jack the Ripper and the East End" at the Museum in Docklands, London, on May 14, 2008. (AP Photo/Akira Suemori)

Last month brought the news that Jack the Ripper had been identified, at least according to an amateur detective who claimed in a new book that DNA evidence from a blood-soaked shawl found near one of the victims pointed to a Polish immigrant named Aaron Kosminski.

But Russell Edwards' claim was dogged by issues: The shawl's provenance was shaky, a peer-reviewed journal hadn't published the finding, and the molecular biologist Edwards used to arrive at his conclusion had to make use of mitochondrial, rather than genomic, DNA.

Now, a fourth hole: That expert, Jari Louhelainen, made a serious "error in nomenclature," according to a group of DNA experts who pored over the finding at casebook.org.

They say these two sentences from Edwards' book are the smoking gun:

"This DNA alteration is known as global private mutation (314.1C) and it is not very common in worldwide population, as it has frequency estimate of 0.000003506, i.e. approximately 1/290,000. This figure has been calculated using the database at Institute of Legal Medicine, GMI, based on the latest available information."

As the Independent reports, the experts say Louhelainen referenced the wrong mutation from the GMI's mtDNA database; it should be "315.1C" rather than "314.1C." And the issue is that 315.1C isn't rare at all.

As one writer on the casebook forum alleges, "The presence of an extra C in this position is much more common than its absence. The database referred to in the book ... indicates that 315.1C is present in 99.2% of the sequences which have information for this position." If we're indeed looking at a match frequency above 90%, rather than 1/290,000, then the match has no significance, as "the same match would have been seen with almost anyone who had handled the shawl over the years," says professor Sir Alec Jeffreys.

Edwards' publisher is investigating the error but notes the finding "relies on much more than this one figure." (Another Jack the Ripper claim: There is no Jack the Ripper.)

This article originally appeared on Newser: Scientists: Jack the Ripper ID Was Based on Error