The most complete research of recent hen genomes thus far has resulted within the reconstruction of the hen household tree, difficult standard notions in regards to the evolutionary trajectory of birds.
Published within the journal Nature, the decade-long study built-in genomic information from greater than 360 species, with data from practically 200 fossils. It is the work of collaborative analysis by scientists worldwide taking part within the Bird 10,000 Genomes Project (B10K), aiming to sequence the whole genomes of each present hen species.
Lead creator Josefin Stiller, a biologist on the University of Copenhagen in Denmark, stated: “Our research has addressed earlier controversies relating to the hen household tree and has added new insights to the established understanding of hen evolution.”
The ‘hen tree of life’, primarily based on the genomes of 363 species. The main hen teams are colour-coded (Jon Fjeldså, Natural History Museum Denmark).
Three main clades
Among the roughly 10,000 residing hen species, three main clades are recognized. Approximately 5% of species belong to both Palaeognathae, encompassing flightless species corresponding to ostriches, cassowaries, and emus, or Galloanseres, together with landfowl and waterfowl. The remaining 95% of hen species represent a 3rd numerous clade: the Neoaves.
The research suggests that almost all Neoaves emerged inside a comparatively brief evolutionary timeframe of solely 5 million years, following the speedy diversification interval after the Cretaceous-Paleogene extinction occasion 66 million years in the past.
Dr Jacqueline Nguyen, avian palaeontologist on the Australian Museum and Flinders University and co-author of the research, commented: “By analysing proof from practically 200 hen fossils, we recognized a vital interval of hen diversification instantly following the dinosaur extinction occasion.”
During this era, vital genetic and morphological adjustments occurred amongst birds, together with heightened mutation charges, decreased physique sizes, bigger brains, and elevated efficient inhabitants sizes.
Relationships for 363 hen species (Josefin Stiller).
Revolutionising views on avian historical past
The findings provide scientists a clearer understanding of the hen household tree, notably inside the Neoaves. The revised tree challenges earlier classifications of Neoaves by reorganizing it into 4 main sub-groups: Mirandornithes, Columbaves, Telluraves, and a newly proposed group named ‘Elementaves’ by the researchers.
Inspired by the weather of earth, air, water, and fireplace, Elementaves consists of birds that thrive on land, within the air and in water, corresponding to penguins, pelicans, hummingbirds and shorebirds.
Guojie Zhang, senior creator of the paper and professor of evolutionary biology at Zhejiang University, China, stated: “Our analysis has revolutionised many standard views on the evolutionary historical past of birds. This up to date household tree will function a sturdy framework for tracing the evolutionary historical past of all hen species, with vital implications for ornithological analysis and biodiversity research.”
Reference
Chowdhury, A A, Feng, S, Stiller, J, et al. 2024. Complexity of avian evolution revealed by family-level genomes. Nature. DOI: doi.org/10.1038/s41586-024-07323-1
