Leveraging ancestry to investigate the genomics of song and colour in birds

Biodiversity abounds with a myriad of forms, colours and behaviours. We are now in the genomic age when scientists can investigate the genes that explain many of the characters we see in the natural world. In birds, recent studies have identified regions of the genome that explain differences in bill size, bill, feather (e.g. Kirschel et al. 2020, Molecular Ecology) as well as bare skin colour, but genes that code for behaviour, such as acoustic communication signals, are more challenging to identify. Characters such as song and colour differentiate one species from another. We can determine how one species divides into two by identifying the changes in the genome that underlie those character differences. Hybrid zones among related species provide an incomparable opportunity to detect genes associated with characters such as colour and song. This is because when two species interbreed and hybrids are viable, genes will cross between the species in concert with specific characters. Working with Bridgett vonHoldt from Princeton University, we are investigating the genes and regulatory regions of the genome that underpin differences in song and plumage in tinkerbirds by sampling extensively across a hybrid zone of two species with discrete and quantifiable song and colour differences and by utilising a chromosome-level reference genome we assembled as part of the vertebrate genome project. The study involves fieldwork in the contact zone in Eswatini (formerly Swaziland) in collaboration with Ara Monadjem at the University of Eswatini, and in Gauteng and KwaZulu-Natal, in collaboration with Colleen Downs at the University of KwaZulu-Natal. We are investigating carotenoids in feathers with Sophia Hayes and Constantina Kapnissi from the Department of Chemistry at the University of Cyprus.

Video: Yellow-fronted tinkerbird recorded in Gauteng, South Africa. The project involved identifying genes explaining forecrown feather colour and song variation.