Saturday, April 14, 2007

Protein links T. rex to chickens

"Protein extracted from 68 million-year-old T. rex bones has shed new light on the evolutionary link between dinosaurs and birds.

Researchers compared organic molecules preserved in the T. rex fossils with those of living animals, and found they were similar to chicken protein.



The discovery of protein in dinosaur bones is a surprise - organic material was not thought to survive this long.

A US team of researchers have published the finding in Science journal.

The team says their technique could help reveal evolutionary relationships between other living and extinct organisms.

The finding is consistent with the idea that birds can trace a direct evolutionary line to dinosaurs.

The proteins are original organic material from the dinosaur's soft tissue, and not contamination, the scientists argue.

According to theories of fossilisation, original organic material is not thought to survive as long as this; finding them in a fossil this old is a genuine surprise. They are by far the oldest such molecules extracted from fossils.

"It has always been assumed that preservation of [dinosaur bones] does not extend to the cellular and molecular level," said co-author Mary Schweitzer, from North Carolina State University in Raleigh, US.

"The pathways of cellular decay are well known for modern organisms. And extrapolations predict that all organics are going to be gone completely in 100,000 years, maximum."

Brooks Hanson, an editor at Science journal said: "The goal of obtaining sequences either from proteins or DNA for extinct [organisms] has been a long-standing goal to test evolutionary links and processes, or even functional information."

The work builds on an earlier discovery of soft tissue - including blood vessels - by Dr Schweitzer's team in the same, incredibly well-preserved Tyrannosaurus rex fossils."

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