DNA matches aren't always a lock
By Jason Felch and Maura Dolan,
Los Angeles Times
| 05. 03. 2008
Police found the naked body of Diana Sylvester near her Christmas tree.
The 22-year-old San Francisco nurse had been sexually assaulted and stabbed in the heart. She lay on her back, her neck laced with scratches and her mouth open as if frozen in a scream.
For more than three decades, Sylvester's slaying went unsolved. Then, in 2004, a search of California's DNA database of criminal offenders yielded an apparent breakthrough: Badly deteriorated DNA from the assailant's sperm was linked to John Puckett, an obese, wheelchair-bound 70-year-old with a history of rape.
The DNA "match" was based on fewer than half of the genetic markers typically used to connect someone to a crime, and there was no other physical evidence.
Puckett insisted he was innocent, saying that although DNA at the crime scene happened to match his, it belonged to someone else.
At Puckett's trial earlier this year, the prosecutor told the jury that the chance of such a coincidence was 1 in 1.1 million.
Jurors were not told, however, the statistic that leading scientists consider the most significant: the...
Related Articles
By Josie Ensor, The Times | 12.09.2025
A fertility start-up that promises to screen embryos to give would-be parents their “best baby” has come under fire for a “misuse of science”.
Nucleus Genomics describes its mission as “IVF for genetic optimisation”, offering advanced embryo testing that allows...
By Hannah Devlin, The Guardian | 12.06.2025
Couples undergoing IVF in the UK are exploiting an apparent legal loophole to rank their embryos based on genetic predictions of IQ, height and health, the Guardian has learned.
The controversial screening technique, which scores embryos based on their DNA...
By Frankie Fattorini, Pharmaceutical Technology | 12.02.2025
Próspera, a charter city on Roatán island in Honduras, hosts two biotechs working to combat ageing through gene therapy, as the organisation behind the city advertises its “flexible” regulatory jurisdiction to attract more developers.
In 2021, Minicircle set up a...
By Vardit Ravitsky, The Hastings Center | 12.04.2025
Embryo testing is advancing fast—but how far is too far? How and where do we draw the line between preventing disease and selecting for “desirable” traits? What are the ethical implications for parents, children, clinicians, and society at large? These...
