Using modern molecular analysis, additional evidence has been collected showing the close phylogenetic relationship between a T. Rex and modern day birds. Soft tissue preservation was amazingly discovered within a 68 million year old fossilised thigh bone from the infamous Tyrannosaurus.
Despite being unable to extract DNA from the bone, it was possible obtain six precious peptides, 89 amino acids in total, which was enough to further establish the relationship between the dinosaurs, birds, and alligators; as predicted from skeletal anatomy. This provides the first molecular evidence for the evolutionary relationships of non-avian dinosaurs. Similar analysis was also achieved with collagen protein sequences derived from a fossilised mastodon bone, showing the close relationship between the extinct beast and a modern day elephant.
Furthermore, using the relationship between genome size and cell size, scientists have also catalogued the specific phylogenetic links between two major lineages of dinosaurs and modern day species. Carnivores such as T. Rex and Velociraptor had very small genomes similar to those of modern day birds, while Ornithischians, including Stegosaurus and Triceratops had moderately sized genomes closer to that of modern day crocodilians and lizards. This brings to light the sincerity of my suggestion when a friend commented that the raptors in Jurassic Park looked so angry, and I replied: "you'd be mad too if you were resurrected in the future only to discover your entire gene pool had amounted to no more than a chicken."
Due to the taxonomic links between modern day species and dinosaurs, it has even been suggested that the possibility of modern dinosaurs remains without access to preserved dinosaur DNA. By taking some bird DNA, essentially dinosaur DNA that has undergone millions of years of evolution, and somehow allowing evolution to proceed in reverse (perhaps 'anti-evolution') for the right amount of time, a blueprint for dinosaur DNA could be the result.
Posted by Alexander Bunt.
http://www.sciencedaily.com/videos/2006/0607-jurassic_docs.htm (interesting medical advances in disease evolution)