face_with_colon_three year 2008.
Putting more meat on the theory that dinosaurs’ closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein — along with that of 21 modern species — confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.
The work, published this week in the journal Science, represents the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree that traces the evolution of species. The scientists also report that similar analysis of 160,000-to 600,000-year-old collagen protein sequences derived from mastodon bone establishes a close phylogenetic relationship between that extinct species and modern elephants.
“These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur,” says co-author Chris Organ, a postdoctoral researcher in organismic and evolutionary biology at Harvard University.
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