Confirming what had been a long-held hypothesis among paleontologists, scientists have now verified at the molecular level that the closest living relatives of Tyrannosaurus rex are indeed birds; most specifically ostriches and chickens. Skeletal evidence has strongly borne this theory out in recent years as data from fossils has accumulated, but this new study of bone proteins definitively shows that more of the T. rex genome is similar to birds' than to living reptiles'.