Monday, 25 August 2008

T-Rex - Chicken Link Looking a bit Tenuous?

Remember that paper published in Science last year? The one that described how researchers at North Carolina State University had extracted collagen fibres from a Tyrannosaurus Rex bone? The one that showed how the T-Rex collagen was similar to collagen taken from chicken bones, and gave us all hopes for extracting biological material - maybe even DNA - from ancient bones?
Yeah. Turns out that the evidence for the T-Rex/Chicken link might be a bit tenuous.

Last month, Tom Kaye at the Burke Museum of Natural History and Culture published a paper in PLoS ONE showing that the collagen that was extracted might not be collagen at all! His paper showed that, instead, it is possible that the "collagen" was a biofilm, a layer of bacterial growth. He explained that "[when] biofilms coat a substrate, and that substrate is subsequently removed, the biofilm will retain much of the original morphology. This can explain the quantity and similarity of structures found in fossil bone and indicates that these structures are unlikely to be preserved dinosaurian tissues but the product of common bacterial activities."

Of course, this doesn't disprove that the sample was collagen. Rather, it provides an alternative interpretation of the data. You can read both papers and weigh the evidence and decide for yourself. However, it does not end there.

Pavel Pevzner et al. at the University of California, San Diego, have written a rather scathing critique of the dinosaur collagen claim (here and here). Calling the original paper "computationally illiterate". He claims that the protein spectra data that has been released so far is insufficient to show the data is statistically significant and cannot rule out false positives. Mary Schweitzer and colleagues, the original paper's authors, have so far kept most of the 48,000 pieces of mass spectrum data under wraps. This comes after they already retracted three of the proteins for not being statistically significant.

Now, I'm not saying that their claim was falsified. But to keep all of their data that should show that their conclusions were relevant hidden is kinda...suspicious. When someone publishes an article claiming that you were looking at slime and not collagen, then wouldn't you want to release the rest of the data to back up your claim? I don't understand how the original paper was published sans data in the first place. Science does not make the matter any better by only publishing the critique online as a "technical comment". Could they be down playing the controversy to keep the sensationalism of the original paper?

Hopefully the creationists don't get their dirty paws all over this. Undoubtedly, they'd use this as fodder for a "evolutionists are faking evidence again. Dinosaurs and birds aren't related" argument. You know how they keep bringing up Piltdown Man...

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