Slashdot Mirror
T. Rex Protein Analysis Supports Dinosaur-Bird Link
LanMan04 writes "For the first time, researchers have read the biological signature of a Tyrannosaur — a signature that confirms the increasingly accepted view that modern birds are the descendants of dinosaurs. Analyzing the organic material (collagen protein) found inside the unique fossil linked the collagen to several extant species. The bottom line is that the T. rex's biological signature was most like a bird's, at least based on the first fragmentary data. "It looks like chicken may be the closest among all species that are present in today's databases for proteins and genomes," one of the scientists interviewed said."
For the most part, it has long been assumed that all dinosaur fossils had little to no organic material inside them. However, there was an incident, something like a year ago, when they couldn't fit a particularly large T-rex bone inside a helicopter, and cut it instead. They noticed that the fossil still had a bit of give on the inside and it looked like fresh tissue. A new study was initiated, and they dissolved the mineralized portion of the bone (and of others). What was left was the springy organic material -- even blood vessels were intact. They were not only able to study the proteins, but they were even able to tell that one of the dinosaurs studied was a brooding female.
Organic preservation like this is still believed to be a rare phenominon, but I'd expect many more ancient fossils to be inspected for organic remains from now on. Too bad DNA is as unstable in the long term as it is, though.
Then the winter came, and the Grasshopper died. And the Octopus ate all his acorns. Also, he got a racecar.
A few references for anyone interested...
John Ostrom of Yale University definitely supported the theory that birds might have evolved from a theropod dinosaur branch back in the early 1980's, I believe. Dr. Ostrom's ideas were then popularized by the publication of Dr. Robert Bakker's book "The Dinosaur Heresies", which is an interesting, colorful read, although admittedly Bakker doesn't always stick strictly to the science and he seems to rely too heavily on cladistic studies which don't take chronologies into consideration.
John Horner's "Digging Dinosaurs" was published not long after "The Dinosaur Heresies" and documents Horner's excavation of fossilized maiasaur nests containing crushed eggshells and bones of juvenile animals with incompletely developed joints, suggesting that they stayed in the nests and were cared for, similar to the way modern birds care for their hatchlings.
In the book "Jurassic Park" it is quite clear that Michael Crichton was aware of the work of Ostrom, Bakker and Horner, and in fact it seemed to me that he modeled his character Alan Grant after John Horner.
Regarding the size of the velociraptors in "Jurassic Park", at the time of its publication I don't recall that any six-foot-tall velociraptors had been discovered. However, a closely related species, Deinonychus, was known at the time, and it actually fits Crichton's description better than the velociraptors that were originally excavated in Asia.
Also, for anyone interested and close enough to visit, Peabody Museum in New Haven, CT has two Deinonychus models (I don't think they're original fossils, which would be quite rare) on display in its great room.
Here is it:
http://www.sciencemag.org/cgi/content/full/316/58
Protein Sequences from Mastodon and Tyrannosaurus Rex Revealed by Mass Spectrometry
Here is a choice quote: A BLAST alignment and similarity search (23) of the five T. rex peptides from collagen {alpha}1t1 as a group against the all-taxa protein database showed 58% sequence identity to chicken, followed by frog (51% identity) and newt (51% identity). The small group of peptide sequence data reported here support phylogenetic hypotheses suggesting that T. rex is most closely related to birds among living organisms whose collagen sequence is present in protein databases (24-26). This article documents previous research:
http://www.sciencemag.org/cgi/content/abstract/31
Analyses of Soft Tissue from Tyrannosaurus rex Suggest the Presence of Protein