DNA link for early birds
2007-03-08 10:25
Paris - The group of dinosaurs that evolved into birds had small genomes, according to a study by US and British biologists that appears on Thursday in the journal Nature.
Birds first appeared on the scene around 110 million years ago and have a very small genetic code compared with other vertebrates.
Harvard University researcher Chris Organ led a team that used statistical techniques and microscopic examination of bone fragments to estimate the size of genomes of 31 species of dinosaurs and extinct birds and of 25 living species of four-limbed creatures, ranging from amphibians to man.
They believe that saurischian dinosaurs, which lived between 230 and 250 million years ago, had small, compact genomes, thus strengthening the argument that avian ancestry lies with this group.
The other big dinosaur group, ornithischians, which gave rise only to terrestrial dinosaurs, had a much bigger genome.