It appears that the much-ballyhooed DNA match that identified a Ripper victim's blood on a 19th-centruy shawl has now turned out to be much less significant than originally claimed. The online Ripperologists who looked critically at this claim seem to have been vindicated.
The Independent, a British paper, reports:
[T]he scientist who carried out the DNA analysis has apparently made a fundamental error that fatally undermines his case against Kosminski – and once again throws open the debate over who the identity of the Ripper.
The scientist, Jari Louhelainen, is said to have made an "error of nomenclature" when using a DNA database to calculate the chances of a genetic match. If true, it would mean his calculations were wrong and that virtually anyone could have left the DNA that he insisted came from the Ripper's victim.
The apparent error, first noticed by crime enthusiasts in Australia blogging on the casebook.org website, has been highlighted by four experts with intimate knowledge of DNA analysis – including Professor Sir Alec Jeffreys, the inventor of genetic fingerprinting – who found that Dr Louhelainen made a basic mistake in analysing the DNA extracted from a shawl supposedly found near the badly disfigured body of Ripper victim Catherine Eddowes. They say the error means no DNA connection can be made between Kosminski and Eddowes ...
[E]xperts with detailed knowledge of the GMI's mtDNA database claimed that Dr Louhelainen made an "error of nomenclature" because the mutation in question should be written as "315.1C" and not "314.1C". Had Dr Louhelainen done this, and followed standard forensic practice, he would have discovered the mutation was not rare at all but shared by more than 99 per cent of people of European descent.
This potential problem was discussed in more detail in an earlier post about the Ripper story. Given the authority of the scientists who are now weighing in, and the continuing silence from Dr. Louhelainen, I'd say the DNA claim has been decisively debunked.
In terms of the usual subject matter of this blog, the take-away is that even experts can make rather obvious mistakes when they get caught up in the excitement of the chase. This can apply both to parapsychologists and their critics. We need to look critically at all claims, whether pro- or anti-paranormal, and keep emotion out of it as much as possible.
Admittedly, easier said than done ...