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Jack the Ripper Genetic ID: Foiled by a Decimal Point?

The DNA analysis that supposedly definitively unveiled the true identity of Jack the Ripper may have been erroneous, according to an article published yesterday in The Independent.

In September The Daily Scan picked up on an item published in the Daily Mail recapping how Russell Edwards, a Jack the Ripper enthusiast who owns a shawl purported to have been collected at the scene of a Ripper killing, enlisted the help of Liverpool John Moores University molecular biologist Jari Louhelainen to conduct forensic analysis on the garment.

The article, which coincided with the release of Edwards' book "Naming Jack the Ripper," detailed the procedure that Louhelainen used to ascertain Jack's true identity, in particular sequencing mitochondrial DNA from bloodstains and a semen stain found on the shawl and testing them against swab samples taken from descendants of Catherine Eddowes, the purported former owner of the shawl, and Polish immigrant Aaron Kosminski, who had been previously suspected but never proven to be the murderer.

Louhelainen did not publish his work in a peer-reviewed journal, instead opting to present it in Edwards' book, which noted that one of the amplified mtDNA segments had a sequence variation — known as global private mutation (314.1C) — that is not very common in the worldwide population and did not match any control reference sequences, but matched sequence data from Eddowes' descendant, Karen Miller.

The 314.1C mutations has a frequency estimate of 0.000003506, or approximately one in 290,000, Louhelainen claimed — a figure that he calculated based on a database at the Institute of Legal Medicine. "Thus, this result indicates the shawl contains human DNA identical to Karen Miller's for this mitochondrial DNA segment," Louhelainen concluded.

Not so fast, yesterday's article in The Independent asserted. Running with information first presented on the website, the article cited various molecular biology experts — including Sir Alec Jeffreys, the inventor of genetic fingerprinting — who noted that Louhelainen made an "error of nomenclature," because the mutation in question should have been written as 315.1C and not 314.1C. The former mutation is not rare at all, but shared by more than 99 percent of people of European descent, meaning the mtDNA mutational match that Louhelainen made could have been made with nearly anyone who had handled the shawl over the years.

Louhelainen "appears to have made a basic error in calculating the frequency estimate," The Independent writes. "There are currently about 34,617 entries in the GMI database, and the figure would have been nearer to 29,000 when Dr. Louhelainen carried out his research some time ago. So failing to find a match for a non-existent mutation should have given a frequency of about [one in] 29,000 — an error suggesting that he had placed a decimal point in the wrong place."

Sidgwick & Jackson, the publishers of Edwards' book, told The Independent that the author is standing by his conclusions, and that the conclusion that Kosminski was indeed Jack the Ripper "relies on much more than this one figure." Nevertheless, they are investigating the reported error.