Mythical PNAS Papers

 
Here's part of a Harvard University Press release issued yesterday.

Beyond a 'speed limit' on mutations, species risk extinction

Genomes of various organisms lose stability with more than 6 mutations per generation

CAMBRIDGE, Mass. -- Harvard University scientists have identified a virtual "speed limit" on the rate of molecular evolution in organisms, and the magic number appears to be 6 mutations per genome per generation -- a level beyond which species run the strong risk of extinction as their genomes lose stability.

By modeling the stability of proteins required for an organism's survival, Eugene Shakhnovich and his colleagues have discovered this essential thermodynamic limit on a species's rate of evolution. Their discovery, published this week in the Proceedings of the National Academy of Sciences, draws a crucial connection between the physical properties of genetic material and the survival fitness of an entire organism.

This sounds very interesting. The limit of six mutations per genome per generation is far less than the calculated mutation rates for mammalian genomes [Mutation Rates] so it looks like another genetic load argument in favor of junk DNA.

So, I set off to retrieve the article that, according to the press release was published in this week's issue of PNAS. But it wasn't. You can see for yourself by looking at the current issue on the website [Sept. 25, 2007].

Not a problem. I've encountered this discrepancy before. What they mean is the issue that's about to be published and the article is available online in prepublication format. All you have to do is check the "Early Edition" (in this case the Oct. 2, 2007 edition) by clicking on the link from the PNAS home page. Except that the paper isn't there either.

Thus, in spite of what it says in the press release, this paper has not been published by PNAS in either the paper issue or online. This is not the first time this has happened. Over the past few months I've tried to find half a dozen mythical PNAS papers that are prominently mentioned in press releases.

Wait a minute ... look at the fine print on the early edition page [Early Edition]. The version that I'm looking at right now says "Last updated October 2, 2007." Right below that is the following statement.

Because PNAS publishes daily online, you may read about an article in the news media on Monday or Tuesday, but the article may not publish online until later in the week. You may use the CiteTrack feature to set up an e-mail alert to notify you as soon as the article you are interested in publishes.

This is unacceptable. If PNAS can't guarantee that a paper will be available when the press release embargo is lifted then they should change the embargo date. Most other journals have a restriction on press releases that delays the promotion of a paper until it is published and we can see for ourselves whether the hype and the reality match. Apparently PNAS is aware of this problem but instead of fixing it by moving the embargo date to Friday they choose to ignore publishing etiquette. This is wrong.