Birdsong and Human Speech
This month (December 2014) sees the culmination of a huge, international effort which has resulted in nearly thirty papers being simultaneously published. Eight of these are appearing in a special edition of Science, including a new paper which focuses specifically on the genes involved in birdsong and compares them to those humans use to learn speech. Human speech is extremely complex and seems unique in the animal kingdom. Many animals can vocalise to some extent but only humans seem to have a true language with grammar and syntax. However, bird song may be equally complex in its structure and more importantly appears to be learnt by young birds in a similar way to how humans learn language. This has long interested students of human speech because it is relatively difficult to study humans in the lab but very easy to keep songbirds.
The 48 species of bird sequenced for this project represent every one of the major bird lineages and offers an unprecedented view of the diversity of genes within birds. It also revealed a few surprises. Since birdsong is so complex many scientists had assumed that it evolved just once but this new study suggests that it evolved twice, possibly three times, independently within the songbirds, parrots and hummingbirds.
The most profound findings though are related to the learning of songs. The study discovered 50 genes which showed high and low activity during vocal learning in birds and these genes are almost identical to those used when humans learn language. Even more tellingly, these genes showed little or no activity in non-vocal learning birds and in non-human primates. This means that in this respect vocal birds are more similar to humans then they are to their non-vocal learning cousins.
Featured Image: Wikimedia Commons