OspreyOliver Kruger
An international research team has described a new bird family tree that promises to reshape our understanding of avian evolution in a new study published this week in the journal Nature.
The most comprehensive and detailed family tree of bird species to date, the study tracks the evolutionary lineage of birds, from those that lived during the dinosaur era to the present day, and includes genetic sequence data from 363 species of birds—representing 92 percent of all bird families.
The study is part of the Bird 10,000 Genomes Project, one of the largest genome sequencing projects in the world, resulting from a collaboration of 52 co-authors from 49 institutions in 13 countries, including from the Museum.
“The great diversity of birds can be difficult to comprehend on a general level and even harder to understand from a scientific viewpoint,” said co-author Joel Cracraft, Lamont Curator in the Museum’s Department of Ornithology. “The evolutionary relationships between living and extinct birds have been long-contested. But this study has succeeded in compiling the massive amount of high-quality data needed to resolve conflicting findings of the past.”
The genetic data were analyzed alongside physical characteristics such as body and brain size, allowing the team to track how evolution has led to differences among species and to pinpoint the underlying genome changes that may have caused them.
The researchers found that there was a rapid increase in the number of bird lineages soon after the mass extinction event that killed the dinosaurs more than 65 million years ago. They also found that although changes to body sizes of birds have slowed over time, there was an increase in brain size that continues through today.
“This illustrates the power of comparative genomics: by comparing genomes of living species, we can uncover traces of events that happened 66 million years ago,” said Josefin Stiller, the lead author of the study and an assistant professor at the University of Copenhagen.