Dinosaur bird links underlined
Thursday, 08 Mar 2007 08:26
Scientists find genetic similarities between dinosaurs and modern day birds
Genetic similarities between dinosaurs and modern birds may be more deep-rooted than previously thought.
According to the latest research, dinosaur genomes have "distinctive" similarities with modern birds in terms of size.
Scientists from Harvard University and the University of Reading say they have been able to gauge the genetic makeup of 31 species of extinct dinosaurs and birds by linking bone cell and genome size to living species.
But researchers were surprised to discover how small the mighty dinosaur genomes actually were; akin to a modern-day hummingbird.
A genome provides scientists with a complete set of genetic information on any given organism.
Study co-author Chris Organ from Harvard University writes in the Nature journal that significant differences exist between two "major lineages of dinosaurs".
"The theropods - carnivores such as Tyrannosaurus rex and Velociraptor - had very small genomes, in the range of modern birds," he reveals.
"Ornithischians - which include Stegosaurus and Triceratops - had more moderately-sized genomes, akin to those of living lizards and crocodilians. We aren't sure about the genomes of the long-necked sauropods yet."
Professor Organ's colleague Scott Edwards elaborates that their research suggests that small genomes associated with birds first evolved in dinosaurs between 230 and 250 million years ago, and not with the emergence of modern birds 110 million years ago.
"Our work debunks the theory that the small, repeat-poor genomes typical of birds may have co-evolved with flight as a means of conserving energy," writes professor Edwards.
"In fact, our work shows these streamlined genomes arose long before the first birds and flight, and can be added to the list of dinosaur traits previously thought to be found only in modern birds, including feathers, pulmonary innovations, and parental care and nesting."