Patricia Cornwell – Portrait Of A Killer Jack The Ripper

When one reads about DNA tests used in modern criminal or pater­nity cases, what is usually being referred to is the nuclear DNA that is located in virtually every cell in the body and passed down from both par­ents. Mitochondrial DNA is found outside the nucleus of the cell. Think of an egg: The nuclear DNA is found in the yolk, so to speak, and the mitochondrial DNA would be found in the egg white. Mitochondrial DNA is passed down only from the mother. While the mitochondrial region of a cell contains thousands more “copies” of DNA than the nucleus does, mitochondrial DNA testing is very complex and expensive, and the results can be limited because the DNA is passed down from only one parent.

The extracts of all fifty-five DNA samples were sent to The Bode Tech­nology Group, an internationally respected private DNA laboratory, best known for assisting the Armed Forces Institute of Pathology (AFIP) in using mitochondrial DNA to determine the identity of America’s Vietnam War Unknown Soldier. More recently, Bode has been using mitochon­drial DNA to identify victims of the 9/11 terrorist attack on the World Trade Center. The examination of our samples took months, and while I was back in London’s Public Record Office with art and paper experts. Dr. Paul Ferrara telephoned to tell me that Bode had finished the testing and had gotten mitochondrial DNA on almost every sample. Most of the genetic profiles were a mishmash of individuals. But six of the samples had the same mitochondrial DNA sequence profile component found on the Openshaw envelope.

“Markers” are locations. Markers in the Ripper/Sickert tests are where the base positions of DNA are located on the D loop sequence of the mitochondrial DNA – which is about as easy for most people to envi­sion as it is for me to understand the mathematical equation for rela­tivity, E = me2. An imposing challenge for DNA experts is to help the hoi polloi understand what DNA is and what test results mean. Posters showing matching fingerprints create a flurry of nods and “oh yes, I get it” looks from jurors. But the analysis of human blood – beyond its screaming fresh red or its old dark dried presence on clothing and weapons and at crime scenes – has always induced catatonia and pin­point pupils in panicky eyes.

ABO blood-group typing was antenna-tangling enough. DNA blows mental transformers, and the hackneyed explanation that a DNA “fin­gerprint” or profile looks like a bar code on a soup can in the grocery store isn’t helpful in the least. I can’t envision my flesh and bones as bil­lions of bar codes that can be scanned in a laboratory and come up as me. So I often use analogies, because I confess that without them I don’t always comprehend the abstractions of science and medicine, even though I write about them for a living.

The swabbed samples in the Jack the Ripper case can be imagined as fifty-five sheets of white paper that are cluttered with thousands of dif­ferent combinations of numbers. Most of the sheets of paper have smears, and illegible numbers, and mixtures of numbers that indicate they came from many different people. However, two sheets of paper each have a sequence of numbers that came from a single donor – or only one per­son: One sheet is James McNeill Whistler, and the other is a partial postage stamp on the back of a letter the Ripper wrote to Dr. Thomas Openshaw, the curator of the London Hospital Museum.

The Whistler sequence has nothing in common with any Ripper letter or any other non-Whistler item tested. But the Openshaw sequence is found in five other samples. These five samples are not single-donor, as far as we can tell at this point, and show a mixture of other base posi­tions or “locations” in the mitochondrial region. This could mean that the sample was contaminated by the DNA of other people. A drawback in our testing is that the ever-elusive Walter Sickert has yet to offer us his DNA profile. When he was cremated, our best evidence went up in flames. Unless we eventually find a premortem sample of his blood, skin, hair, teeth, or bones, we will never resurrect Walter Richard Sickert in a laboratory. But we may have found pieces of him.