When researchers retrieved the thigh bone of a Tyrannosaurus rex from nearly 100 million years under the Montana soil, they probably didn’t have Jurassic Park theme running through their heads. Yet when the bone yielded a small sample of collagen protein, some of the oldest preserved protein ever found, paleontology and biochemistry finally began to merge. The protein yielded a sequence and the sequence settled an evolutionary debate that has roiled anatomists since the 19th century.
We know that dinosaurs’ and birds’ archosaur ancestor split off from the lizards long ago, we have skeletal evidence linking dinosaurs and birds and several transition species have been found that don’t fit neatly into either dinosaur or bird. If that didn’t nail the case, the collagen sequence certainly should.
Protein retrieved from a 68 millon-year-old Tyrannosaurus rex bone closely resembles the main protein in chicken and ostrich bones and is only distantly related to lizards’, strengthening the popular idea that birds, and not reptiles, are the closest living relatives of dinosaurs.
The new work builds on a 2007 analysis showing remarkably close similarities between T. rex collagen and collagen from modern-day chickens, but that work did not include comparisons to other living species. Collagen is the primary protein in bones.
No doubt science will soon tackle the obvious next step – exactly how many genetic changes do we need to get a 50-foot, meat eating chicken that runs 45 miles an hour? I can’t imagine any possible downside.