International project maps genetic evolution of birds

A massive international scientific project has for the first time mapped the genetic evolution of birds and revealed how they developed characteristics like feathers, flight and song.

The studies, involving 200 scientists across 80 institutions in 20 countries, saw the genome, or genetic fingerprint, of 48 varieties of birds completely decoded and compared with each other for the first time over the course of four years. 

The results, detailed in 28 research papers published in the journal Science and other academic publications, show a burst of evolution lasting 10-15m years took place after the mass extinction of the dinosaurs 66m years ago.

This step change, the research claims, led to the development of nearly all of the 10,000 species of birds that we have on Earth today.

The scientists were able to draw these conclusions because they compared the bird genomes with those of three other reptile species and humans, to see at which point in each of the species evolution they developed unique features.

The researchers also discovered that birdsong evolved independently at least twice.

Surprisingly parrots and songbirds developed their ability to learn and mimic vocal activity despite sharing many of the same genes.

The scientists also discovered that vocal learning birds and humans share 50 similar gene changes in their brain circuitry.

The research describes how birds are evolving much faster than crocodilians - like crocodiles, turtles and other reptiles - despite the fact birds developed from them.

Chickens were found to have the most similar chromosome pattern to avian ancestors, thought to be a feathered dinosaur.

The scientists also found that mutations that led to the elimination of teeth and development of toothless beaks in modern birds began around 116 million years ago. 

The new genetic family tree also suggests that the earliest common ancestor of land birds, including parrots and songbirds, hawks and eagles, was an animal at the top of its food chain - known as an apex predator.

It also shows that water birds evolved in three different strands, independent of one another.

The findings also help to explain why bird genomes are in general 70% smaller than those of mammals, and highlight how specific regions of the birds genetic blueprint have been conserved for more than 100 million years. 

Among the species that were genetically profiled as part of the Avian Phylogenomics Project are the crow, duck, falcon, parakeet, woodpecker, owl, penguin, hummingbird and flamingo.

Scientists say the work is significant because birds - which are the most species rich class of four limbed vertebrates on the planet - can help us answer fundamental questions in biology and ecology, and are also an important source of food.

The avian genome consortium is now creating a database that will be made publicly available in the future for scientists to study the genetic basis of complex avian traits.