Science magazine withdraws controversial study of bacteria that lived on arsenic fifteen years later

On December 2, 2010, Science, one of the world's most prestigious scientific journals, published a study online that caused a media stir and a fierce controversy . The research announced the discovery of a new life form, a bacterium found in Mono Lake, California, that grew by incorporating arsenic, one of the world's worst poisons, into its DNA. NASA, which funded the work, presented it in a press conference with great fanfare as proof of "arsenic life," a major breakthrough in astrobiology. Fifteen years later, Science has retracted the study.

The article, written by Felisa Wolfe-Simon of the NASA Astrobiology Institute and her team, was met with skepticism by the scientific community, which immediately raised serious questions about both the results and the way the experiments were conducted. The avalanche of comments led the journal to postpone its print publication until June 3, 2011, when it finally appeared, along with eight technical comments, a response from the authors, and a note from Editor-in-Chief Bruce Alberts explaining the decision and the timing.

A year later, the journal published two more articles that clearly refuted the results: they showed that the GFAJ-1 bacterium was highly resistant to arsenic, but did not use it to develop as a substitute for phosphorus. In other words, we were not dealing with a unique living being, but rather one that acted like all other life we know on Earth.

One of the technical comments noted that the nucleic acids analyzed were not sufficiently purified and that the results were the result of contamination. However, Science did not retract the study, exonerating the authors of fraud or deliberate misconduct. Although it still maintains this opinion, it does so now, almost fifteen years later, because it has expanded the grounds for retracting an article after consulting with the Committee on Publication Ethics (COPE). Thus, if the experiments do not support its key conclusions, even if there is no fraud or manipulation, a retraction is considered appropriate.

For their part, all of the article's authors, except for one who has since passed away and another who declined to join his colleagues, have signed a letter expressing their disagreement. "While our work could have been written and analyzed more carefully, we stand by the data as presented. They were peer-reviewed, openly debated, and stimulated productive research," they argue in the letter. In it, they emphasize that "disputes over the conclusions of articles are a normal part of the scientific process" and that they foster it, sometimes even for decades.

César Ángel Menor Salvan, professor of Biochemistry at the University of Alcalá, disagrees with the retraction. "We always thought that arsenic-based life was chemically impossible, and we used this article as an example of flawed science. I've even used it in class as a case study for students, in exercises in which they had to evaluate why the work reached incorrect conclusions," he explains to the Science Media Centre (SMC) . However, "there was no misconduct or lack of professionalism on the part of the authors; these were simply errors in the interpretation and discussion of experimental data, something common in science and nothing wrong with that. On the contrary, it shows that discussing scientific results works and that science advances, leaving behind misconceptions or incorrect interpretations," he emphasizes. "The retraction is as controversial as the article itself and has been quite painful at NASA, where they have long fought to avoid it." "That's why I think (unlike many colleagues) that it's excessive, as it carries a negative reputational burden that is perhaps unfair," he adds.

Andrés de la Escosura Navazo, a researcher at the Institute for Advanced Research in Chemical Sciences (IAdChem) and the Department of Organic Chemistry at the Autonomous University of Madrid (UAM), supports the decision of 'Science'. "If results appear to lead to conclusions that radically change the paradigm of a branch of knowledge, to such an extent that it implies the need to modify textbooks, the system must question them even more rigorously than is usual in science," he says. In his opinion, "the expectations created and excessive media coverage can hinder such critical analysis. This is probably what happened on this occasion."

'Science' just wants to end the controversy: "We hope this decision puts an end to the story."