- After the original report, Pevzner (privately) pointed out statistical problems, and the authors revised their findings, admitting in a letter to Science in September 2007 that one of the peptide fragments was a statistical artifact. One down, six remaining.
- In January 2008, Science published a new Technical Comment in which 27 authors (Buckley et al.) used a standard set of authentication tests developed for ancient DNA, and reported that the T. rex sample failed those tests. (Another sample from mastodon, also reported by Asara but 100 times younger, passed the same tests.)
- In July 2008, Thomas Kaye and colleagues published a report that re-examined the microscope evidence of the T. rex "soft tissue". The original findings by Schweitzer were based on this soft "tissue" being original T. rex organic material. Kaye et al. report that the soft material was a bacterial biofilm - not original material at all. They also report on carbon dating of the biofilm showing it to be modern, not ancient.
- Pevzner et al. report this week that the peptide mass spectrometry evidence - which Asara and Schweitzer repeatedly used to defend their results against the earlier criticism - are also flawed. One way to resolve this, Pevzner points out, is to release the mass spec data, which is a common practice in that community. This would allow others to re-interpret the data and test more rigorously for statistical artifacts. However, Asara and Schweitzer refuse to release their data. Instead, they wrote another response which simply gives more details about how they ran the software to search their spectra against a peptide database, but doesn't really answer Pevzner's questions.
If Science truly cared about getting this story right, they would publish the critiques just as prominently as the original article. It seems that Science is eager to get publicity for a "discovery", but not so eager for publicity when it turns out the discovery is false. Yes, it's true that they did publish the critiques, but they should have done better.
Finally, I recommend Rex Dalton's story in Nature on this controversy, which does a good job of summing it up, with links to all the articles. We'll see what happens next, but it appears that Schweitzer and Asara will keep defending their claims. The mounting evidence seems to show that they were wrong - wrong about the soft tissue, wrong about the mass spec identifications, wrong about the age of the sample, and wrong to continue to refuse to release their data.