Even more questions are being asked about a high-profile paper in Nature which claimed that a type of adult stem cell was as versatile as human embryonic stem cells. In June 2002 Catherine Verfaillie, of the University of Minnesota, characterised multipotent adult progenitor cells (MAPCs) which seemed to be able to grow into most of the body's tissues. However, her results were difficult to reproduce and were greeted with much scepticism amongst her colleagues.

Digging through Verfaillie's data in several papers, New Scientist discovered that some of the images in her ground-breaking paper were flawed. Now its investigative journalists have pushed the lode of errors even deeper by studying a patent relating to MAPCs granted to a company in Cleveland, Athersys. Once again, images had been modified and used to support different conclusions. Investigations are continuing, but it appears possible that one of Verfaillie's junior colleagues may have fudged results. Investigations are continuing.