Reacción a "‘Science’ retracts controversial article on bacteria that used arsenic to grow, published in 2010"

The letter that the journal Science has just published retracting the article by Wolfe-Simon and colleagues is important because it closes a controversy that has lasted 15 years, since the original publication in 2010. To provide a brief historical overview, the article described a type of bacteria (GFAJ-1) living in California's Mono Lake that was capable of growing by incorporating arsenic instead of phosphorus into its DNA. The work raised doubts from the outset, as revealed by the fact that the print version was published (in 2011) accompanied by eight comments from other scientists who were experts in the field, expressing varying degrees of doubt about the discovery.

In response to the doubts and criticism raised in the scientific community, the authors agreed to share the bacterial samples so that other laboratories could investigate them, and approximately two years later, in 2012, the journal Science itself published two articles that clearly refuted the results and conclusions of Wolfe-Simon's team. The first of these, published by Julia Vorholt's team, proved that these bacteria are actually highly resistant to arsenic and can grow in the presence of very low levels of phosphate. High resistance to arsenic is not in fact a unique property of these bacteria; other organisms, including eukaryotes, can live in this extremely arsenic-rich environment. On the other hand, Rosemary Redfield's team demonstrated the inadequate purification of the DNA analyzed in the original article. By avoiding contamination of the bacterial DNA, Redfield and her colleagues found only traces of arsenic in it.

What is surprising about this case is the long time that has elapsed since the first articles refuting Wolfe-Simon's work and her final retraction. The journal cites as the reason for this delay that there were never any indications of scientific misconduct on the part of the authors, and that only when the standards established by the Committee on Publication Ethics (COPE) were expanded to also take into account cases where the data does not support the conclusions of a paper did they proceed to retract the paper. From a scientific point of view, this assumption is quite obvious. It is true that the article has sparked intense scientific debate and stimulated further research on these extremophile microorganisms, as the authors argue in a letter also published by the journal, in which they express their disagreement with the decision. It is worth asking, however, whether all this debate has really been productive, and also about the excessive media coverage of some scientific organizations and certain lines of research. It should not be forgotten that the article by Wolfe-Simon and colleagues was announced with great fanfare at a press conference held by NASA, which now seems clearly excessive.

If results appear to lead to conclusions that radically change the paradigm of a branch of knowledge, to such an extent that it becomes necessary to modify textbooks, then the system must question those conclusions even more rigorously than is usual in science. However, the expectations created and excessive media coverage can hinder such critical analysis. This is probably what happened on this occasion. Both the journal and the authors acknowledge in their letters that things could have been done differently.