Tyrannosaurus Rex 'was more like a chicken than a crocodile'
The largest carnivore that ever walked the planet – Tyrannosaurus rex – is more closely related to the modern chicken than it is to living reptiles such as the alligator or crocodile, a study of the dinosaur's fossilised protein has found.
Researchers analysed a tiny shred of 68-million-year-old protein taken from the leg of T. Rex and compared it to the same protein found in 21 modern species. They confirmed that the giant predator is closely related to chickens and ostriches, but only to a lesser extent to reptiles such as alligators and crocodiles, which were thought to be more closely related to dinosaurs than other living creatures.
It is the first time that scientists have been able to trace a relationship between dinosaurs and birds through molecular analysis of animal protein, although anatomical studies have already produced convincing evidence of a link between birds and dinosaurs.
"These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur," said Chris Organ, a researcher in evolutionary biology at Harvard University in the US.
Proteins are composed of amino-acids arranged in a sequence that mirrors the order of chemical bases on molecules of DNA, so scientists can look at short strands of protein– called peptides – to investigate the relationships between species: alive or dead.
"Even though we only had six peptides – just 89 amino-acids – from T. rex, we were able to establish these relationships with a relatively high degree of support," Dr Organ said. "With more data, we would likely see the T. rex branch on the phylogenetic tree between alligators and chickens and ostriches, though we cannot resolve this position with currently available data."
John Asara and Lewis Cantley, of Harvard Medical School, were the first experts to capture and sequence pieces of collagen protein from T. rex. The samples were taken from the thigh bone of a T. rex unearthed in the "badlands" of Wyoming and Montana. "Most of the collagen sequence was obtained from protein and genome databases," Dr Asara said, "but we also needed to sequence some critical organisms, including modern alligator and modern ostrich.
"We determined that T. rex grouped with birds – ostrich and chicken – better than any other organism that we studied. We also showed that it groups better with birds than modern reptiles, such as alligators and green anole lizards."
The study, published in the latest edition of the journal Science, will add to the growing evidence that birds are descended directly from a group of dinosaurs that grew feathers, possibly as a form of thermal insulation, before they learnt to fly.
In China, scientists have found many examples of feathered dinosaurs, including several that may have used their wings to glide. One fossilised dinosaur had feathers growing in both pairs of limbs, suggesting that four-winged flight may have been possible among some species.
- 4 #JeSuisEd: People share photos of themselves eating awkwardly in solidarity with Labour leader
- 5 Women think Irish men are the sexiest, survey finds
In defence of liberal democracy
General Election 2015: Post-election 'shambles' looms as 70 per cent of voters say SNP 'should not be able to veto UK government policies'
The Rothschild Libel: Why has it taken 200 years for an anti-Semitic slur that emerged from the Battle of Waterloo to be dismissed?
General Election 2015: UK will be 'run for the wealthy and powerful' if Tories retain power, Labour warns
General election live: SNP suspends two members for disrupting Labour rally
General Election 2015: Sturgeon claims Scots 'appalled' by Ed Miliband's refusal to work with SNP
£35000 - £40000 per annum + car and benefits: Ashdown Group: Marketing Manager...
£18000 - £20000 per annum: Ashdown Group: Helpdesk Analyst - Devon - £20,000 ...
£35000 - £50000 per annum + generous bonus: Ashdown Group: Business Analytics ...
£45000 - £50000 per annum: Ashdown Group: IT Project Coordinator (Software Dev...