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Scientists have managed to extract proteins of collagen 1 from the bones of a 68-million-years-old Tyrannosaurus rex fossil. It was previously thought the protein in bones had a shelf life of around a million years. By comparison, DNA "survives" less than 100,000 years.

The collagen protein was discovered in a thighbone unearthed four years ago under 20 yards of rock on a cliff in the Hell Creek Formation, which spans the Wyoming, Montana and the Dakotas in the northwestern U.S. Reporting in two papers in the new issue of Science, the team of researchers announced that a chemical analysis of the T. rex peptides suggests the king of the lizards is most similar to a present-day chicken.

However, this affirmation is part speculation. The similarity between the proteins from dinosaurs and chickens may only be due to the fact that other animals, such as crocodiles and alligators, have not had their proteins or genomes sequenced yet. As such, this claim was not the main focus of the papers.

"The data from both papers support the hypothesis that original protein may be preserved, but at such low levels they're barely detectable," says study co-author Mary Schweitzer, a molecular paleontologist at North Carolina State University.

Bone is a composite material, consisting of both protein and mineral. When minerals are removed from modern bone, a collagen matrix – fibrous, resilient material that gives the bone its structure and flexibility – is left behind. When Schweitzer demineralized the T. rex bone, she was surprised to find such a matrix, because current theories of fossilization held that no original organic material could survive that long.

Then they tested it against various antibodies that are known to react with collagen.

"We looked for collagen because it's plentiful, it's durable, and it has been recovered from other fossil materials, although none as old as this T. rex," Schweitzer says. "It's also a relatively easy molecule to identify, and it's not something that any microbes living in the immediate environment could produce. So identifying collagen in the soft tissue would indicate that it is original to the T. rex – that the tissue contains remnants of the molecules produced by the dinosaur, though highly altered."

Subsequently, she turned for confirmation to another expert who specializes in a mass spectrometry technique developed for studying low-level proteins in human diseases.

"We were successful in purifying enough peptides in order to cross the threshold of the mass spectrometer and reveal sequences," says Harvard Medical School pathologist and mass spectrometry expert John Asara, adding that the T. rex specimen yielded seven sequences. "When you look at these set[s] of sequences, they, as a whole set, have the closest similarity to [those of a] chicken, which would support the previous reports that birds evolved from dinosaurs or are closely related at least."

"As far as the hypothesis that protein would not survive more than a million years," he notes, "we have obviously proven that to be false."

Lewis Cantley, a Harvard biology professor on the team, said: "Basically, this is the breakthrough that says it's possible to get sequences beyond 1 million years."

"It's terrifically interesting," said Eddy Rubin, director of the Energy Department's Joint Genome Institute in Walnut Creek, Calif., to WP. "It really does say that biological molecules survive way longer than anyone thought."

There are also hopes that the new techniques developed could be applied in the medical field. Lewis Cantley, a systems biologist at Harvard Medical School, said, "Our goal would be to take a biopsy of bone from a prostate cancer patient, and from a very minute amount of material, extracted from a needle, be able to sequence proteins that are at very low abundance—oncoproteins, for example that drive the tumor—and even identify mutations in the protein sequence that tell us why that person got that disease."

Meanwhile, the search is on for more well-preserved specimens of dinosaur fossils, well-kept isolated under sedimentary rock.

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