How birds evolved to have characteristics including feathers, flight and song is revealed with new clarity in a major study of their family tree.

The international study charts a burst of evolution that took place after the mass extinction of dinosaurs, 66 million years ago. This change gave rise to nearly all of the bird species on the planet today – more than 10,000 varieties.

The four year project, which included researchers from the University of Edinburgh’s Roslin Institute, decoded and compared the entire genetic fingerprint of 48 bird species.

The study provides new insights into how bird genes differ from those of mammals, and the biological mechanism that give rise to the vast diversity among birds. Researchers compared the genomes of the 48 bird species with those of three other reptile species and humans. This enabled them to investigate at which point in each species’ history specialized characteristics developed.

“This is just the beginning. Ultimately, we hope the research will bring important insights to help improve the health and welfare of wild and farmed birds,” said Professor David Burt, acting director the National Avian Research Facility at the Roslin Institute.

Building on the research, scientists at the National Avian Research Facility have created 48 open access databases to share and expand on the information associated with the birds’ genomes. They hope that researchers will continue to upload their own data, offering further insights into the genetics of modern birds. Such information will be useful for helping scientists understand why infectious diseases, such as avian influenza, affect some species but not others.