Scientists have put more meat on the theory that dinosaurs' closest living relatives are modern-day birds.
Molecular analysis, or genetic sequencing, of a 68-million-year-old Tyrannosaurus rex protein from the dinosaur's femur confirms that T. rex shares a common ancestry with chickens, ostriches, and to a lesser extent, alligators.
The dinosaur protein was wrested from a fossil T. rex femur discovered in 2003 by paleontologist John Horner of the Museum of the Rockies; the bone was found in a fossil-rich stretch of land in Wyoming and Montana.
The new research results, published this week in the journal Science, represent the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree, a "tree of life," that traces the evolution of species.
"These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur," says Science paper co-author Chris Organ, a researcher at Harvard University. "Even though we only had six peptides--just 89 amino acids--from T. rex, we were able to establish these relationships."
"Tests of the peptide sequences in T. rex bone fossils have confirmed that newer methods of molecular systematics agree with more traditional methods of taxonomic classification based on morphology, or shapes," says Paul Filmer, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.
Paper co-author Mary Schweitzer of North Carolina State University (NCSU) and the North Carolina Museum of Natural Sciences first discovered the soft-tissue preservation in the T. rex bone in 2005.
The current paper builds on work reported in Science last year. In that paper, a team headed by John Asara and Lewis Cantley, both of Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School (HMS), first captured and sequenced tiny piec
|Contact: Cheryl Dybas|
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