Sir

As your Editorial “Standards for papers on cloning” (Nature 439, 243; 2006) demonstrates, the fraudulent Hwang stem-cell research papers will have consequences for future research in this and related biomedical fields. As you point out, this does not justify imposing more rigorous standards for reviewing manuscripts in this field than others. Enforcing the deposition of samples with independent laboratories or repositories would be inappropriate, and deposition could also be done fraudulently. Although deposition might allow another layer of supervision, it would also create another layer of complexity and cost to stymie further research in a field already encumbered by restrictions.

As researchers in different parts of this field, we would like to make a joint response. We believe a simpler system of checks and balances could reduce incidents of scientific fraud and increase our confidence in published reports.

First, all co-authors should indicate the scope of their involvement and declare their understanding of the data in, for example, an author contribution statement such as that recommended by Nature (http://www.nature.com/nature/authors/gta). Surprisingly, it seems clear in retrospect that many of the 26 authors on Hwang's report (Science 308, 1777–1783; 2005), could not have attested to the veracity of the human nuclear-transfer embryonic stem cells (ntESC) presented. A requirement for personal accountability might have encouraged greater communication between authors and uncovered the deception before publication.

Second, all journals should, like Nature (http://www.nature.com/nature/authors/policy), require that all published reagents and cell lines be made available to other laboratories.

Finally, peer reviewers should be encouraged to demand that authors provide clear and strong evidence that the data presented support the claims made — including the request for mitochondrial DNA fingerprints if appropriate.

Of course, the best way to ensure integrity in any field is independent replication of results, which requires multiple investigators to be free to do the research. Current limits on US federal funding make independent verification of results especially challenging in the case of human ESC or ntESC research, and undoubtedly contributed to the difficulties in uncovering the misconduct of Hwang and his colleagues.