Genetic Tests Suggest STAP Stem Cells ‘Never Existed’

Reports of a new kind of stem cell, produced by simply stressing mature mouse cells, kicked up a storm of controversy soon after their publication in Nature on 30 January. Duplicated and manipulated images as well as plagiarism were found in the two papers, which led to a verdict of misconduct for the lead author, Haruko Obokata of the RIKEN Center for Developmental Biology in Kobe, Japan. There have also been calls for a retraction (which, for at least one of the papers, looks increasingly likely). But the controversy has left open a key question: does the phenomenon, known as stimulus-triggered acquisition of pluripotency, or STAP, exist?

The answer, according to Japanese media reports today on the results of genetic tests on the cells used in the STAP experiments, is no.

STAP cells were claimed to be made by exposing bodily cells to acid or subjecting them to physical pressure. These cells take on characteristics of embryonic stem cells. If further manipulated, they will also form self-renewing stem cell lines, called STAP stem cells, which share most...