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."Continued on the NSF website.